Make all C main functions without arguments have "void" in arg list.
diff --git a/test cases/common/1 trivial/trivial.c b/test cases/common/1 trivial/trivial.c
index 38b58cc..96612d4 100644
--- a/test cases/common/1 trivial/trivial.c
+++ b/test cases/common/1 trivial/trivial.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("Trivial test is working.\n");
     return 0;
 }
diff --git a/test cases/common/100 stringdef/stringdef.c b/test cases/common/100 stringdef/stringdef.c
index f1f1ca4..17e29fd 100644
--- a/test cases/common/100 stringdef/stringdef.c
+++ b/test cases/common/100 stringdef/stringdef.c
@@ -1,7 +1,7 @@
 #include<stdio.h>
 #include<string.h>
 
-int main() {
+int main(void) {
     if(strcmp(FOO, "bar")) {
         printf("FOO is misquoted: %s\n", FOO);
         return 1;
diff --git a/test cases/common/102 subproject subdir/prog.c b/test cases/common/102 subproject subdir/prog.c
index cf6f425..9035ff1 100644
--- a/test cases/common/102 subproject subdir/prog.c
+++ b/test cases/common/102 subproject subdir/prog.c
@@ -1,5 +1,5 @@
 #include <sub.h>
 
-int main() {
+int main(void) {
     return sub();
 }
diff --git a/test cases/common/103 postconf/prog.c b/test cases/common/103 postconf/prog.c
index 9315f86..85a25a3 100644
--- a/test cases/common/103 postconf/prog.c
+++ b/test cases/common/103 postconf/prog.c
@@ -1,5 +1,5 @@
 #include"generated.h"
 
-int main() {
+int main(void) {
     return THE_NUMBER != 9;
 }
diff --git a/test cases/common/104 postconf with args/prog.c b/test cases/common/104 postconf with args/prog.c
index 6458543..5db9d17 100644
--- a/test cases/common/104 postconf with args/prog.c
+++ b/test cases/common/104 postconf with args/prog.c
@@ -1,5 +1,5 @@
 #include"generated.h"
 
-int main() {
+int main(void) {
     return THE_NUMBER != 9 || THE_ARG1 != 5 || THE_ARG2 != 33;
 }
diff --git a/test cases/common/106 extract same name/main.c b/test cases/common/106 extract same name/main.c
index 79e70a2..e917d24 100644
--- a/test cases/common/106 extract same name/main.c
+++ b/test cases/common/106 extract same name/main.c
@@ -1,6 +1,6 @@
 int func1();
 int func2();
 
-int main() {
+int main(void) {
     return !(func1() == 23 && func2() == 42);
 }
diff --git a/test cases/common/109 generatorcustom/main.c b/test cases/common/109 generatorcustom/main.c
index 23f894f..4b6857d 100644
--- a/test cases/common/109 generatorcustom/main.c
+++ b/test cases/common/109 generatorcustom/main.c
@@ -2,6 +2,6 @@
 
 #include"alltogether.h"
 
-int main() {
+int main(void) {
     return 0;
 }
diff --git a/test cases/common/11 subdir/subdir/prog.c b/test cases/common/11 subdir/subdir/prog.c
index 76e8197..78f2de1 100644
--- a/test cases/common/11 subdir/subdir/prog.c
+++ b/test cases/common/11 subdir/subdir/prog.c
@@ -1 +1 @@
-int main() { return 0; }
+int main(void) { return 0; }
diff --git a/test cases/common/111 spaces backslash/comparer-end-notstring.c b/test cases/common/111 spaces backslash/comparer-end-notstring.c
index a50ad6d..8b8190f 100644
--- a/test cases/common/111 spaces backslash/comparer-end-notstring.c
+++ b/test cases/common/111 spaces backslash/comparer-end-notstring.c
@@ -10,7 +10,7 @@
 
 #define COMPARE_WITH "foo\\bar\\" /* This is the literal `foo\bar\` */
 
-int main() {
+int main(void) {
     if(strcmp(QUOTE(DEF_WITH_BACKSLASH), COMPARE_WITH)) {
         printf("Arg string is quoted incorrectly: %s instead of %s\n",
                QUOTE(DEF_WITH_BACKSLASH), COMPARE_WITH);
diff --git a/test cases/common/111 spaces backslash/comparer-end.c b/test cases/common/111 spaces backslash/comparer-end.c
index 60c6bdb..8cff1b1 100644
--- a/test cases/common/111 spaces backslash/comparer-end.c
+++ b/test cases/common/111 spaces backslash/comparer-end.c
@@ -6,7 +6,7 @@
 
 #define COMPARE_WITH "foo\\bar\\" /* This is `foo\bar\` */
 
-int main () {
+int main(void) {
     if (strcmp (DEF_WITH_BACKSLASH, COMPARE_WITH)) {
         printf ("Arg string is quoted incorrectly: %s vs %s\n",
                 DEF_WITH_BACKSLASH, COMPARE_WITH);
diff --git a/test cases/common/111 spaces backslash/comparer.c b/test cases/common/111 spaces backslash/comparer.c
index e705ff3..7e3033e 100644
--- a/test cases/common/111 spaces backslash/comparer.c
+++ b/test cases/common/111 spaces backslash/comparer.c
@@ -6,7 +6,7 @@
 
 #define COMPARE_WITH "foo\\bar" /* This is the literal `foo\bar` */
 
-int main () {
+int main(void) {
     if (strcmp (DEF_WITH_BACKSLASH, COMPARE_WITH)) {
         printf ("Arg string is quoted incorrectly: %s instead of %s\n",
                 DEF_WITH_BACKSLASH, COMPARE_WITH);
diff --git a/test cases/common/116 subdir subproject/prog/prog.c b/test cases/common/116 subdir subproject/prog/prog.c
index cf6f425..9035ff1 100644
--- a/test cases/common/116 subdir subproject/prog/prog.c
+++ b/test cases/common/116 subdir subproject/prog/prog.c
@@ -1,5 +1,5 @@
 #include <sub.h>
 
-int main() {
+int main(void) {
     return sub();
 }
diff --git a/test cases/common/119 subproject project arguments/exe.c b/test cases/common/119 subproject project arguments/exe.c
index b338846..e8f2271 100644
--- a/test cases/common/119 subproject project arguments/exe.c
+++ b/test cases/common/119 subproject project arguments/exe.c
@@ -22,6 +22,6 @@
 #error
 #endif
 
-int main() {
+int main(void) {
     return 0;
 }
diff --git a/test cases/common/119 subproject project arguments/subprojects/subexe/subexe.c b/test cases/common/119 subproject project arguments/subprojects/subexe/subexe.c
index 62cc965..bd5316d 100644
--- a/test cases/common/119 subproject project arguments/subprojects/subexe/subexe.c
+++ b/test cases/common/119 subproject project arguments/subprojects/subexe/subexe.c
@@ -22,6 +22,6 @@
 #error
 #endif
 
-int main() {
+int main(void) {
     return 0;
 }
diff --git a/test cases/common/120 test skip/test_skip.c b/test cases/common/120 test skip/test_skip.c
index 24ea97b..59c134b 100644
--- a/test cases/common/120 test skip/test_skip.c
+++ b/test cases/common/120 test skip/test_skip.c
@@ -1,3 +1,3 @@
-int main() {
+int main(void) {
     return 77;
 }
diff --git a/test cases/common/122 llvm ir and assembly/main.c b/test cases/common/122 llvm ir and assembly/main.c
index 887c64a..35e8ed6 100644
--- a/test cases/common/122 llvm ir and assembly/main.c
+++ b/test cases/common/122 llvm ir and assembly/main.c
@@ -2,7 +2,7 @@
 
 unsigned square_unsigned (unsigned a);
 
-int main ()
+int main(void)
 {
   unsigned int ret = square_unsigned (2);
   if (ret != 4) {
diff --git a/test cases/common/124 extract all shared library/prog.c b/test cases/common/124 extract all shared library/prog.c
index 48e7680..de0cc7f 100644
--- a/test cases/common/124 extract all shared library/prog.c
+++ b/test cases/common/124 extract all shared library/prog.c
@@ -1,7 +1,7 @@
 #include"extractor.h"
 #include<stdio.h>
 
-int main() {
+int main(void) {
     if((1+2+3+4) != (func1() + func2() + func3() + func4())) {
         printf("Arithmetic is fail.\n");
         return 1;
diff --git a/test cases/common/125 object only target/prog.c b/test cases/common/125 object only target/prog.c
index 09f2790..dc468ec 100644
--- a/test cases/common/125 object only target/prog.c
+++ b/test cases/common/125 object only target/prog.c
@@ -2,6 +2,6 @@
 int func2_in_obj();
 int func3_in_obj();
 
-int main() {
+int main(void) {
     return func1_in_obj() + func2_in_obj() + func3_in_obj();
 }
diff --git a/test cases/common/126 no buildincdir/prog.c b/test cases/common/126 no buildincdir/prog.c
index 7e9d194..b356f65 100644
--- a/test cases/common/126 no buildincdir/prog.c
+++ b/test cases/common/126 no buildincdir/prog.c
@@ -1,5 +1,5 @@
 #include"header.h"
 
-int main() {
+int main(void) {
     return 0;
 }
diff --git a/test cases/common/128 dependency file generation/main .c b/test cases/common/128 dependency file generation/main .c
index 4cce7f6..03b2213 100644
--- a/test cases/common/128 dependency file generation/main .c
+++ b/test cases/common/128 dependency file generation/main .c
@@ -1,3 +1,3 @@
-int main() {
+int main(void) {
   return 0;
 }
diff --git a/test cases/common/129 configure file in generator/src/main.c b/test cases/common/129 configure file in generator/src/main.c
index 3ee83e6..6329e47 100644
--- a/test cases/common/129 configure file in generator/src/main.c
+++ b/test cases/common/129 configure file in generator/src/main.c
@@ -12,6 +12,6 @@
 #error Source RESULT is not defined correctly
 #endif
 
-int main() {
+int main(void) {
     return 0;
 }
diff --git a/test cases/common/13 pch/c/prog.c b/test cases/common/13 pch/c/prog.c
index ee6df21..12b790e 100644
--- a/test cases/common/13 pch/c/prog.c
+++ b/test cases/common/13 pch/c/prog.c
@@ -4,7 +4,7 @@
     fprintf(stdout, "This is a function that fails if stdio is not #included.\n");
 }
 
-int main() {
+int main(void) {
     return 0;
 }
 
diff --git a/test cases/common/13 pch/generated/prog.c b/test cases/common/13 pch/generated/prog.c
index e1601c9..6765ac1 100644
--- a/test cases/common/13 pch/generated/prog.c
+++ b/test cases/common/13 pch/generated/prog.c
@@ -1,6 +1,6 @@
 // No includes here, they need to come from the PCH
 
-int main() {
+int main(void) {
     return FOO + BAR;
 }
 
diff --git a/test cases/common/13 pch/userDefined/prog.c b/test cases/common/13 pch/userDefined/prog.c
index c7b713a..475131b 100644
--- a/test cases/common/13 pch/userDefined/prog.c
+++ b/test cases/common/13 pch/userDefined/prog.c
@@ -1,6 +1,6 @@
 // No includes here, they need to come from the PCH
 
-int main() {
+int main(void) {
     // Method is implemented in pch.c.
     // This makes sure that we can properly handle user defined
     // pch implementation files and not only auto-generated ones.
diff --git a/test cases/common/13 pch/withIncludeDirectories/prog.c b/test cases/common/13 pch/withIncludeDirectories/prog.c
index ee6df21..12b790e 100644
--- a/test cases/common/13 pch/withIncludeDirectories/prog.c
+++ b/test cases/common/13 pch/withIncludeDirectories/prog.c
@@ -4,7 +4,7 @@
     fprintf(stdout, "This is a function that fails if stdio is not #included.\n");
 }
 
-int main() {
+int main(void) {
     return 0;
 }
 
diff --git a/test cases/common/130 generated llvm ir/main.c b/test cases/common/130 generated llvm ir/main.c
index 887c64a..35e8ed6 100644
--- a/test cases/common/130 generated llvm ir/main.c
+++ b/test cases/common/130 generated llvm ir/main.c
@@ -2,7 +2,7 @@
 
 unsigned square_unsigned (unsigned a);
 
-int main ()
+int main(void)
 {
   unsigned int ret = square_unsigned (2);
   if (ret != 4) {
diff --git a/test cases/common/131 generated assembly/main.c b/test cases/common/131 generated assembly/main.c
index 708eeb5..fb38f9d 100644
--- a/test cases/common/131 generated assembly/main.c
+++ b/test cases/common/131 generated assembly/main.c
@@ -5,7 +5,7 @@
 #endif
 unsigned square_unsigned (unsigned a);
 
-int main ()
+int main(void)
 {
   unsigned int ret = square_unsigned (2);
   if (ret != 4) {
diff --git a/test cases/common/132 build by default targets in tests/main.c b/test cases/common/132 build by default targets in tests/main.c
index 49e3a51..03b2213 100644
--- a/test cases/common/132 build by default targets in tests/main.c
+++ b/test cases/common/132 build by default targets in tests/main.c
@@ -1,3 +1,3 @@
-int main () {
+int main(void) {
   return 0;
 }
diff --git a/test cases/common/133 build by default/foo.c b/test cases/common/133 build by default/foo.c
index 0e6f7a0..0322828 100644
--- a/test cases/common/133 build by default/foo.c
+++ b/test cases/common/133 build by default/foo.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("Existentialism.\n");
     return 0;
 }
diff --git a/test cases/common/134 include order/ordertest.c b/test cases/common/134 include order/ordertest.c
index a5896b4..775e34f 100644
--- a/test cases/common/134 include order/ordertest.c
+++ b/test cases/common/134 include order/ordertest.c
@@ -4,7 +4,7 @@
 #error "Should have picked up hdr.h from inc1/hdr.h"
 #endif
 
-int main ()
+int main(void)
 {
   return 0;
 }
diff --git a/test cases/common/134 include order/sub4/main.c b/test cases/common/134 include order/sub4/main.c
index 77417dd..89226a4 100644
--- a/test cases/common/134 include order/sub4/main.c
+++ b/test cases/common/134 include order/sub4/main.c
@@ -1,7 +1,7 @@
 /* Use the <> include notation to force searching in include directories */
 #include <main.h>
 
-int main() {
+int main(void) {
   if (somefunc() == 1984)
     return 0;
   return 1;
diff --git a/test cases/common/135 override options/four.c b/test cases/common/135 override options/four.c
index 2ab126d..7c85448 100644
--- a/test cases/common/135 override options/four.c
+++ b/test cases/common/135 override options/four.c
@@ -4,6 +4,6 @@
     return -4;
 }
 
-int main() {
+int main(void) {
     return duplicate_func() + func();
 }
diff --git a/test cases/common/135 override options/two.c b/test cases/common/135 override options/two.c
index f3082a6..0f8048c 100644
--- a/test cases/common/135 override options/two.c
+++ b/test cases/common/135 override options/two.c
@@ -1,6 +1,6 @@
 /*
  * Requires a Unity build. Otherwise hidden_func is not specified.
  */
-int main() {
+int main(void) {
     return hidden_func();
 }
diff --git a/test cases/common/137 c cpp and asm/main.c b/test cases/common/137 c cpp and asm/main.c
index 66985ed..293258f 100644
--- a/test cases/common/137 c cpp and asm/main.c
+++ b/test cases/common/137 c cpp and asm/main.c
@@ -2,7 +2,7 @@
 
 int get_retval(void);
 
-int main() {
+int main(void) {
   printf("C seems to be working.\n");
   return get_retval();
 }
diff --git a/test cases/common/139 custom target object output/progdir/prog.c b/test cases/common/139 custom target object output/progdir/prog.c
index d2648bb..9c82659 100644
--- a/test cases/common/139 custom target object output/progdir/prog.c
+++ b/test cases/common/139 custom target object output/progdir/prog.c
@@ -1,5 +1,5 @@
 int func1_in_obj();
 
-int main() {
+int main(void) {
     return func1_in_obj();
 }
diff --git a/test cases/common/14 configure file/dumpprog.c b/test cases/common/14 configure file/dumpprog.c
index 80410f2..9f63b23 100644
--- a/test cases/common/14 configure file/dumpprog.c
+++ b/test cases/common/14 configure file/dumpprog.c
@@ -15,7 +15,7 @@
 #define stringify(s) str(s)
 #define str(s) #s
 
-int main() {
+int main(void) {
 #if !(SHOULD_BE_UNQUOTED_STRING == string)
         printf("String token (unquoted) defined wrong.\n");
         return 1;
diff --git a/test cases/common/14 configure file/prog.c b/test cases/common/14 configure file/prog.c
index 332e3bb..85e66b9 100644
--- a/test cases/common/14 configure file/prog.c
+++ b/test cases/common/14 configure file/prog.c
@@ -8,7 +8,7 @@
 #error "FAIL!"
 #endif
 
-int main() {
+int main(void) {
 #ifndef BE_TRUE
     return 1;
 #else
diff --git a/test cases/common/14 configure file/prog2.c b/test cases/common/14 configure file/prog2.c
index 2aff40c..8b90bfb 100644
--- a/test cases/common/14 configure file/prog2.c
+++ b/test cases/common/14 configure file/prog2.c
@@ -1,5 +1,5 @@
 #include<config2.h>
 
-int main() {
+int main(void) {
     return ZERO_RESULT;
 }
diff --git a/test cases/common/14 configure file/prog4.c b/test cases/common/14 configure file/prog4.c
index 7ee4f49..1e32a31 100644
--- a/test cases/common/14 configure file/prog4.c
+++ b/test cases/common/14 configure file/prog4.c
@@ -1,6 +1,6 @@
 #include <config4a.h>
 #include <config4b.h>
 
-int main() {
+int main(void) {
     return RESULTA + RESULTB;
 }
diff --git a/test cases/common/14 configure file/prog5.c b/test cases/common/14 configure file/prog5.c
index f387530..1a8f785 100644
--- a/test cases/common/14 configure file/prog5.c
+++ b/test cases/common/14 configure file/prog5.c
@@ -1,6 +1,6 @@
 #include <string.h>
 #include <config5.h>
 
-int main() {
+int main(void) {
     return strcmp(MESSAGE, "@var2@");
 }
diff --git a/test cases/common/14 configure file/prog6.c b/test cases/common/14 configure file/prog6.c
index eecd63e..57f5586 100644
--- a/test cases/common/14 configure file/prog6.c
+++ b/test cases/common/14 configure file/prog6.c
@@ -1,7 +1,7 @@
 #include <string.h>
 #include <config6.h>
 
-int main() {
+int main(void) {
     return strcmp(MESSAGE1, "foo")
         || strcmp(MESSAGE2, "@var1@")
         || strcmp(MESSAGE3, "\\foo")
diff --git a/test cases/common/14 configure file/prog7.c b/test cases/common/14 configure file/prog7.c
index a0e6f75..802bc46 100644
--- a/test cases/common/14 configure file/prog7.c
+++ b/test cases/common/14 configure file/prog7.c
@@ -1,7 +1,7 @@
 #include <string.h>
 #include <config7.h>
 
-int main() {
+int main(void) {
     return strcmp(MESSAGE1, "foo")
         || strcmp(MESSAGE2, "${var1}")
         || strcmp(MESSAGE3, "\\foo")
diff --git a/test cases/common/14 configure file/prog9.c b/test cases/common/14 configure file/prog9.c
index 7180a26..3f77601 100644
--- a/test cases/common/14 configure file/prog9.c
+++ b/test cases/common/14 configure file/prog9.c
@@ -10,7 +10,7 @@
 #error "Should be defined"
 #endif
 
-int main() {
+int main(void) {
     return strcmp(A_STRING, "foo")
         || strcmp(B_STRING, "foo")
         || A_INT != 42
diff --git a/test cases/common/141 whole archive/prog.c b/test cases/common/141 whole archive/prog.c
index c6eb045..1f553e5 100644
--- a/test cases/common/141 whole archive/prog.c
+++ b/test cases/common/141 whole archive/prog.c
@@ -1,5 +1,5 @@
 #include<mylib.h>
 
-int main() {
+int main(void) {
     return func1() - func2();
 }
diff --git a/test cases/common/146 nested links/xephyr.c b/test cases/common/146 nested links/xephyr.c
index 33c14ce..9b6bdc2 100644
--- a/test cases/common/146 nested links/xephyr.c
+++ b/test cases/common/146 nested links/xephyr.c
@@ -1,3 +1,3 @@
-int main() {
+int main(void) {
     return 0;
 }
diff --git a/test cases/common/148 link depends custom target/foo.c b/test cases/common/148 link depends custom target/foo.c
index 8700a9e..58c86a6 100644
--- a/test cases/common/148 link depends custom target/foo.c
+++ b/test cases/common/148 link depends custom target/foo.c
@@ -1,6 +1,6 @@
 #include <stdio.h>
 
-int main() {
+int main(void) {
   const char *fn = DEPFILE;
   FILE *f = fopen(fn, "r");
   if (!f) {
diff --git a/test cases/common/149 recursive linking/circular/main.c b/test cases/common/149 recursive linking/circular/main.c
index a419333..164abdf 100644
--- a/test cases/common/149 recursive linking/circular/main.c
+++ b/test cases/common/149 recursive linking/circular/main.c
@@ -6,7 +6,7 @@
 int get_st2_value (void);
 int get_st3_value (void);
 
-int main() {
+int main(void) {
   int val;
 
   val = get_st1_value ();
diff --git a/test cases/common/149 recursive linking/edge-cases/shstmain.c b/test cases/common/149 recursive linking/edge-cases/shstmain.c
index 6598c72..334f867 100644
--- a/test cases/common/149 recursive linking/edge-cases/shstmain.c
+++ b/test cases/common/149 recursive linking/edge-cases/shstmain.c
@@ -4,7 +4,7 @@
 
 int get_stshdep_value (void);
 
-int main() {
+int main(void) {
   int val;
 
   val = get_stshdep_value ();
diff --git a/test cases/common/149 recursive linking/edge-cases/stomain.c b/test cases/common/149 recursive linking/edge-cases/stomain.c
index 544ece9..a16a89b 100644
--- a/test cases/common/149 recursive linking/edge-cases/stomain.c
+++ b/test cases/common/149 recursive linking/edge-cases/stomain.c
@@ -4,7 +4,7 @@
 
 int get_stodep_value (void);
 
-int main() {
+int main(void) {
   int val;
 
   val = get_stodep_value ();
diff --git a/test cases/common/149 recursive linking/main.c b/test cases/common/149 recursive linking/main.c
index 2ddcb88..cf091d0 100644
--- a/test cases/common/149 recursive linking/main.c
+++ b/test cases/common/149 recursive linking/main.c
@@ -9,7 +9,7 @@
 SYMBOL_IMPORT int get_shshdep_value (void);
 SYMBOL_IMPORT int get_shstdep_value (void);
 
-int main() {
+int main(void) {
   int val;
 
   val = get_shnodep_value ();
diff --git a/test cases/common/15 if/prog.c b/test cases/common/15 if/prog.c
index 76e8197..78f2de1 100644
--- a/test cases/common/15 if/prog.c
+++ b/test cases/common/15 if/prog.c
@@ -1 +1 @@
-int main() { return 0; }
+int main(void) { return 0; }
diff --git a/test cases/common/150 library at root/main/main.c b/test cases/common/150 library at root/main/main.c
index c4e1b4e..eadf7e8 100644
--- a/test cases/common/150 library at root/main/main.c
+++ b/test cases/common/150 library at root/main/main.c
@@ -1,5 +1,5 @@
 extern int fn(void);
 
-int main() {
+int main(void) {
     return 1 + fn();
 }
diff --git a/test cases/common/151 simd/simdchecker.c b/test cases/common/151 simd/simdchecker.c
index 3593828..c7a0a97 100644
--- a/test cases/common/151 simd/simdchecker.c
+++ b/test cases/common/151 simd/simdchecker.c
@@ -23,7 +23,7 @@
     return rv;
 }
 
-int main() {
+int main(void) {
     static const float four_initial[4] = {2.0, 3.0, 4.0, 5.0};
     ALIGN_16 float four[4];
     const float expected[4] = {3.0, 4.0, 5.0, 6.0};
diff --git a/test cases/common/153 dotinclude/dotproc.c b/test cases/common/153 dotinclude/dotproc.c
index d8f3829..f48c330 100644
--- a/test cases/common/153 dotinclude/dotproc.c
+++ b/test cases/common/153 dotinclude/dotproc.c
@@ -4,7 +4,7 @@
 #error The wrapper stdio.h was not included.
 #endif
 
-int main() {
+int main(void) {
     printf("Eventually I got printed.\n");
     return 0;
 }
diff --git a/test cases/common/154 reserved targets/test.c b/test cases/common/154 reserved targets/test.c
index 4cce7f6..03b2213 100644
--- a/test cases/common/154 reserved targets/test.c
+++ b/test cases/common/154 reserved targets/test.c
@@ -1,3 +1,3 @@
-int main() {
+int main(void) {
   return 0;
 }
diff --git a/test cases/common/155 duplicate source names/dir1/file.c b/test cases/common/155 duplicate source names/dir1/file.c
index 094e187..1c4753e 100644
--- a/test cases/common/155 duplicate source names/dir1/file.c
+++ b/test cases/common/155 duplicate source names/dir1/file.c
@@ -3,7 +3,7 @@
 extern int dir3;
 extern int dir3_dir1;
 
-int main() {
+int main(void) {
     if (dir2 != 20)
         return 1;
     if (dir2_dir1 != 21)
diff --git a/test cases/common/157 wrap file should not failed/src/subprojects/foo/prog2.c b/test cases/common/157 wrap file should not failed/src/subprojects/foo/prog2.c
index dc14736..849b400 100644
--- a/test cases/common/157 wrap file should not failed/src/subprojects/foo/prog2.c
+++ b/test cases/common/157 wrap file should not failed/src/subprojects/foo/prog2.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("Do not have a file layout like this in your own projects.\n");
     printf("This is only to test that this works.\n");
     return 0;
diff --git a/test cases/common/157 wrap file should not failed/src/subprojects/prog.c b/test cases/common/157 wrap file should not failed/src/subprojects/prog.c
index dc14736..849b400 100644
--- a/test cases/common/157 wrap file should not failed/src/subprojects/prog.c
+++ b/test cases/common/157 wrap file should not failed/src/subprojects/prog.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("Do not have a file layout like this in your own projects.\n");
     printf("This is only to test that this works.\n");
     return 0;
diff --git a/test cases/common/158 includedir subproj/prog.c b/test cases/common/158 includedir subproj/prog.c
index f388ef8..03b2213 100644
--- a/test cases/common/158 includedir subproj/prog.c
+++ b/test cases/common/158 includedir subproj/prog.c
@@ -1,4 +1,3 @@
-
-int main() {
+int main(void) {
   return 0;
 }
diff --git a/test cases/common/159 subproject dir name collision/a.c b/test cases/common/159 subproject dir name collision/a.c
index db85d41..5b1208d 100644
--- a/test cases/common/159 subproject dir name collision/a.c
+++ b/test cases/common/159 subproject dir name collision/a.c
@@ -2,7 +2,7 @@
 char func_b();
 char func_c();
 
-int main() {
+int main(void) {
     if(func_b() != 'b') {
         return 1;
     }
diff --git a/test cases/common/16 else/prog.c b/test cases/common/16 else/prog.c
index 76e8197..78f2de1 100644
--- a/test cases/common/16 else/prog.c
+++ b/test cases/common/16 else/prog.c
@@ -1 +1 @@
-int main() { return 0; }
+int main(void) { return 0; }
diff --git a/test cases/common/17 comparison/prog.c b/test cases/common/17 comparison/prog.c
index 76e8197..78f2de1 100644
--- a/test cases/common/17 comparison/prog.c
+++ b/test cases/common/17 comparison/prog.c
@@ -1 +1 @@
-int main() { return 0; }
+int main(void) { return 0; }
diff --git a/test cases/common/170 get project license/bar.c b/test cases/common/170 get project license/bar.c
index cc34d94..f1bd822 100644
--- a/test cases/common/170 get project license/bar.c
+++ b/test cases/common/170 get project license/bar.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("I'm a main project bar.\n");
     return 0;
 }
diff --git a/test cases/common/172 subproject nested subproject dirs/prog.c b/test cases/common/172 subproject nested subproject dirs/prog.c
index 0bb5253..5536c36 100644
--- a/test cases/common/172 subproject nested subproject dirs/prog.c
+++ b/test cases/common/172 subproject nested subproject dirs/prog.c
@@ -1,5 +1,5 @@
 int func();
 
-int main() {
+int main(void) {
     return func() == 42 ? 0 : 1;
 }
diff --git a/test cases/common/173 preserve gendir/testprog.c b/test cases/common/173 preserve gendir/testprog.c
index 4484f22..b6a9926 100644
--- a/test cases/common/173 preserve gendir/testprog.c
+++ b/test cases/common/173 preserve gendir/testprog.c
@@ -1,6 +1,6 @@
 #include"base.h"
 #include"com/mesonbuild/subbie.h"
 
-int main() {
+int main(void) {
     return base() + subbie();
 }
diff --git a/test cases/common/174 source in dep/generated/main.c b/test cases/common/174 source in dep/generated/main.c
index 75203cb..1ab980a 100644
--- a/test cases/common/174 source in dep/generated/main.c
+++ b/test cases/common/174 source in dep/generated/main.c
@@ -1,5 +1,5 @@
 #include"funheader.h"
 
-int main() {
+int main(void) {
     return my_wonderful_function() != 42;
 }
diff --git a/test cases/common/175 generator link whole/main.c b/test cases/common/175 generator link whole/main.c
index acf8717..7605022 100644
--- a/test cases/common/175 generator link whole/main.c
+++ b/test cases/common/175 generator link whole/main.c
@@ -2,7 +2,7 @@
 
 #include <stdio.h>
 
-int main() {
+int main(void) {
     if (meson_test_function() != 19) {
         printf("Bad meson_test_function()\n");
         return 1;
diff --git a/test cases/common/18 array/prog.c b/test cases/common/18 array/prog.c
index faad956..51204b9 100644
--- a/test cases/common/18 array/prog.c
+++ b/test cases/common/18 array/prog.c
@@ -1,3 +1,3 @@
 extern int func();
 
-int main() { return func(); }
+int main(void) { return func(); }
diff --git a/test cases/common/183 bothlibraries/main.c b/test cases/common/183 bothlibraries/main.c
index b02e048..9b6e39d 100644
--- a/test cases/common/183 bothlibraries/main.c
+++ b/test cases/common/183 bothlibraries/main.c
@@ -3,6 +3,6 @@
 DO_IMPORT int func();
 DO_IMPORT int retval;
 
-int main() {
+int main(void) {
     return func() == retval ? 0 : 1;
 }
diff --git a/test cases/common/184 escape and unicode/main.c b/test cases/common/184 escape and unicode/main.c
index 0bcde16..3435125 100644
--- a/test cases/common/184 escape and unicode/main.c
+++ b/test cases/common/184 escape and unicode/main.c
@@ -4,7 +4,7 @@
 
 int a_fun();
 
-int main() {
+int main(void) {
     if(strcmp(does_it_work(), "yes it does") != 0) {
         return -a_fun();
     }
diff --git a/test cases/common/187 find override/otherdir/main.c b/test cases/common/187 find override/otherdir/main.c
index c442282..b3c39c9 100644
--- a/test cases/common/187 find override/otherdir/main.c
+++ b/test cases/common/187 find override/otherdir/main.c
@@ -1,5 +1,5 @@
 int be_seeing_you();
 
-int main() {
+int main(void) {
     return be_seeing_you() == 6 ? 0 : 1;
 }
diff --git a/test cases/common/187 find override/otherdir/main2.c b/test cases/common/187 find override/otherdir/main2.c
index e1f00c9..522fcbd 100644
--- a/test cases/common/187 find override/otherdir/main2.c
+++ b/test cases/common/187 find override/otherdir/main2.c
@@ -1,5 +1,5 @@
 int number_returner();
 
-int main() {
+int main(void) {
     return number_returner() == 100 ? 0 : 1;
 }
diff --git a/test cases/common/188 partial dependency/declare_dependency/main.c b/test cases/common/188 partial dependency/declare_dependency/main.c
index e9ed032..057b713 100644
--- a/test cases/common/188 partial dependency/declare_dependency/main.c
+++ b/test cases/common/188 partial dependency/declare_dependency/main.c
@@ -15,7 +15,7 @@
 
 #include "foo.h"
 
-int main() {
+int main(void) {
     int a = foo();
     if (a == 1) {
         return 0;
diff --git a/test cases/common/19 includedir/src/prog.c b/test cases/common/19 includedir/src/prog.c
index eb9e2e2..ce4dd67 100644
--- a/test cases/common/19 includedir/src/prog.c
+++ b/test cases/common/19 includedir/src/prog.c
@@ -1,5 +1,5 @@
 #include "func.h"
 
-int main() {
+int main(void) {
     return func();
 }
diff --git a/test cases/common/195 install_mode/trivial.c b/test cases/common/195 install_mode/trivial.c
index 38b58cc..96612d4 100644
--- a/test cases/common/195 install_mode/trivial.c
+++ b/test cases/common/195 install_mode/trivial.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("Trivial test is working.\n");
     return 0;
 }
diff --git a/test cases/common/20 header in file list/prog.c b/test cases/common/20 header in file list/prog.c
index a9216a6..97acb3f 100644
--- a/test cases/common/20 header in file list/prog.c
+++ b/test cases/common/20 header in file list/prog.c
@@ -1,3 +1,3 @@
 #include "header.h"
 
-int main() { return 0; }
+int main(void) { return 0; }
diff --git a/test cases/common/200 generator in subdir/com/mesonbuild/testprog.c b/test cases/common/200 generator in subdir/com/mesonbuild/testprog.c
index 5ea0cb3..7a7cdf7 100644
--- a/test cases/common/200 generator in subdir/com/mesonbuild/testprog.c
+++ b/test cases/common/200 generator in subdir/com/mesonbuild/testprog.c
@@ -1,5 +1,5 @@
 #include"subbie.h"
 
-int main() {
+int main(void) {
     return subbie();
 }
diff --git a/test cases/common/202 subproject with features/nothing.c b/test cases/common/202 subproject with features/nothing.c
index 5bc5493..58fe692 100644
--- a/test cases/common/202 subproject with features/nothing.c
+++ b/test cases/common/202 subproject with features/nothing.c
@@ -1,4 +1,4 @@
-int main()
+int main(void)
 {
     return 0;
-}
\ No newline at end of file
+}
diff --git a/test cases/common/207 kwarg entry/prog.c b/test cases/common/207 kwarg entry/prog.c
index 6d1e2f9..2eec26b 100644
--- a/test cases/common/207 kwarg entry/prog.c
+++ b/test cases/common/207 kwarg entry/prog.c
@@ -1,7 +1,7 @@
 #include<prog.h>
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf(MESSAGE);
     return 0;
 }
diff --git a/test cases/common/215 link custom/prog.c b/test cases/common/215 link custom/prog.c
index 22487c5..2273b1d 100644
--- a/test cases/common/215 link custom/prog.c
+++ b/test cases/common/215 link custom/prog.c
@@ -1,6 +1,6 @@
 void flob();
 
-int main() {
+int main(void) {
     flob();
     return 0;
 }
diff --git a/test cases/common/216 link custom_i single from multiple/prog.c b/test cases/common/216 link custom_i single from multiple/prog.c
index 7826d74..46d10c7 100644
--- a/test cases/common/216 link custom_i single from multiple/prog.c
+++ b/test cases/common/216 link custom_i single from multiple/prog.c
@@ -1,5 +1,5 @@
 int flob();
 
-int main() {
+int main(void) {
     return (flob() == 1 ? 0 : 1);
 }
diff --git a/test cases/common/217 link custom_i multiple from multiple/prog.c b/test cases/common/217 link custom_i multiple from multiple/prog.c
index 3476899..2d626ef 100644
--- a/test cases/common/217 link custom_i multiple from multiple/prog.c
+++ b/test cases/common/217 link custom_i multiple from multiple/prog.c
@@ -1,7 +1,7 @@
 void flob_1();
 void flob_2();
 
-int main() {
+int main(void) {
     flob_1();
     flob_2();
     return 0;
diff --git a/test cases/common/225 include_dir dot/src/main.c b/test cases/common/225 include_dir dot/src/main.c
index 31f6046..192b783 100644
--- a/test cases/common/225 include_dir dot/src/main.c
+++ b/test cases/common/225 include_dir dot/src/main.c
@@ -1,5 +1,5 @@
 #include "rone.h"
 
-int main() {
+int main(void) {
     return rOne();
-}
\ No newline at end of file
+}
diff --git a/test cases/common/23 object extraction/main.c b/test cases/common/23 object extraction/main.c
index 0bb5253..5536c36 100644
--- a/test cases/common/23 object extraction/main.c
+++ b/test cases/common/23 object extraction/main.c
@@ -1,5 +1,5 @@
 int func();
 
-int main() {
+int main(void) {
     return func() == 42 ? 0 : 1;
 }
diff --git a/test cases/common/24 endian/prog.c b/test cases/common/24 endian/prog.c
index b598b7a..90bd958 100644
--- a/test cases/common/24 endian/prog.c
+++ b/test cases/common/24 endian/prog.c
@@ -8,7 +8,7 @@
 }
 
 
-int main() {
+int main(void) {
     int is_be_check = is_big_endian();
     int is_be;
 #ifdef IS_BE
diff --git a/test cases/common/26 config subdir/src/prog.c b/test cases/common/26 config subdir/src/prog.c
index 15a10d1..b9db890 100644
--- a/test cases/common/26 config subdir/src/prog.c
+++ b/test cases/common/26 config subdir/src/prog.c
@@ -1,5 +1,5 @@
 #include "config.h"
 
-int main() {
+int main(void) {
     return RETURN_VALUE;
 }
diff --git a/test cases/common/27 pipeline/depends/prog.c b/test cases/common/27 pipeline/depends/prog.c
index f438a00..8bd6e03 100644
--- a/test cases/common/27 pipeline/depends/prog.c
+++ b/test cases/common/27 pipeline/depends/prog.c
@@ -1,5 +1,5 @@
 int func();
 
-int main() {
+int main(void) {
     return func() != 42;
 }
diff --git a/test cases/common/27 pipeline/prog.c b/test cases/common/27 pipeline/prog.c
index 458fc84..7bd54d4 100644
--- a/test cases/common/27 pipeline/prog.c
+++ b/test cases/common/27 pipeline/prog.c
@@ -1,5 +1,5 @@
 int func();
 
-int main() {
+int main(void) {
     return func();
 }
diff --git a/test cases/common/27 pipeline/src/prog.c b/test cases/common/27 pipeline/src/prog.c
index e693d8a..83121b5 100644
--- a/test cases/common/27 pipeline/src/prog.c
+++ b/test cases/common/27 pipeline/src/prog.c
@@ -1,6 +1,6 @@
 #include"input_src.h"
 
-int main() {
+int main(void) {
     void *foo = printf;
     if(foo) {
         return 0;
diff --git a/test cases/common/33 define10/prog.c b/test cases/common/33 define10/prog.c
index d13995b..519b40d 100644
--- a/test cases/common/33 define10/prog.c
+++ b/test cases/common/33 define10/prog.c
@@ -1,7 +1,7 @@
 #include<stdio.h>
 #include"config.h"
 
-int main() {
+int main(void) {
     if(ONE != 1) {
         fprintf(stderr, "ONE is not 1.\n");
         return 1;
diff --git a/test cases/common/36 tryrun/ok.c b/test cases/common/36 tryrun/ok.c
index 0c987d9..e2a36c8 100644
--- a/test cases/common/36 tryrun/ok.c
+++ b/test cases/common/36 tryrun/ok.c
@@ -1,5 +1,6 @@
 #include<stdio.h>
-int main() {
+
+int main(void) {
   printf("%s\n", "stdout");
   fprintf(stderr, "%s\n", "stderr");
   return 0;
diff --git a/test cases/common/42 library chain/main.c b/test cases/common/42 library chain/main.c
index 7b015b7..7754755 100644
--- a/test cases/common/42 library chain/main.c
+++ b/test cases/common/42 library chain/main.c
@@ -1,5 +1,5 @@
 int libfun();
 
-int main() {
+int main(void) {
   return libfun();
 }
diff --git a/test cases/common/44 test args/env2vars.c b/test cases/common/44 test args/env2vars.c
index f6c8ba3..e940c9a 100644
--- a/test cases/common/44 test args/env2vars.c
+++ b/test cases/common/44 test args/env2vars.c
@@ -2,7 +2,7 @@
 #include<string.h>
 #include<stdlib.h>
 
-int main() {
+int main(void) {
     if(strcmp(getenv("first"), "something-else") != 0) {
         fprintf(stderr, "First envvar is wrong. %s\n", getenv("first"));
         return 1;
diff --git a/test cases/common/44 test args/envvars.c b/test cases/common/44 test args/envvars.c
index e40cc9b..086b0be 100644
--- a/test cases/common/44 test args/envvars.c
+++ b/test cases/common/44 test args/envvars.c
@@ -2,7 +2,7 @@
 #include<string.h>
 #include<stdlib.h>
 
-int main() {
+int main(void) {
     if(strcmp(getenv("first"), "val1") != 0) {
         fprintf(stderr, "First envvar is wrong. %s\n", getenv("first"));
         return 1;
diff --git a/test cases/common/45 subproject/subprojects/sublib/simpletest.c b/test cases/common/45 subproject/subprojects/sublib/simpletest.c
index 01d0f25..2184bc6 100644
--- a/test cases/common/45 subproject/subprojects/sublib/simpletest.c
+++ b/test cases/common/45 subproject/subprojects/sublib/simpletest.c
@@ -1,5 +1,5 @@
 #include<subdefs.h>
 
-int main() {
+int main(void) {
     return subfunc() == 42 ? 0 : 1;
 }
diff --git a/test cases/common/45 subproject/user.c b/test cases/common/45 subproject/user.c
index ec34477..9181622 100644
--- a/test cases/common/45 subproject/user.c
+++ b/test cases/common/45 subproject/user.c
@@ -2,7 +2,7 @@
 #include<stdio.h>
 
 
-int main() {
+int main(void) {
     int res;
     printf("Calling into sublib now.\n");
     res = subfunc();
diff --git a/test cases/common/48 custom install dirs/prog.c b/test cases/common/48 custom install dirs/prog.c
index 33c14ce..9b6bdc2 100644
--- a/test cases/common/48 custom install dirs/prog.c
+++ b/test cases/common/48 custom install dirs/prog.c
@@ -1,3 +1,3 @@
-int main() {
+int main(void) {
     return 0;
 }
diff --git a/test cases/common/49 subproject subproject/prog.c b/test cases/common/49 subproject subproject/prog.c
index 0bb5253..5536c36 100644
--- a/test cases/common/49 subproject subproject/prog.c
+++ b/test cases/common/49 subproject subproject/prog.c
@@ -1,5 +1,5 @@
 int func();
 
-int main() {
+int main(void) {
     return func() == 42 ? 0 : 1;
 }
diff --git a/test cases/common/5 linkstatic/main.c b/test cases/common/5 linkstatic/main.c
index 458fc84..7bd54d4 100644
--- a/test cases/common/5 linkstatic/main.c
+++ b/test cases/common/5 linkstatic/main.c
@@ -1,5 +1,5 @@
 int func();
 
-int main() {
+int main(void) {
     return func();
 }
diff --git a/test cases/common/50 same file name/prog.c b/test cases/common/50 same file name/prog.c
index 6e3628e..61bc874 100644
--- a/test cases/common/50 same file name/prog.c
+++ b/test cases/common/50 same file name/prog.c
@@ -1,6 +1,6 @@
 int func1();
 int func2();
 
-int main() {
+int main(void) {
     return func1() - func2();
 }
diff --git a/test cases/common/51 file grabber/prog.c b/test cases/common/51 file grabber/prog.c
index 581b0e7..47ccc30 100644
--- a/test cases/common/51 file grabber/prog.c
+++ b/test cases/common/51 file grabber/prog.c
@@ -2,6 +2,6 @@
 int funcb();
 int funcc();
 
-int main() {
+int main(void) {
     return funca() + funcb() + funcc();
 }
diff --git a/test cases/common/51 file grabber/subdir/subprog.c b/test cases/common/51 file grabber/subdir/subprog.c
index 581b0e7..47ccc30 100644
--- a/test cases/common/51 file grabber/subdir/subprog.c
+++ b/test cases/common/51 file grabber/subdir/subprog.c
@@ -2,6 +2,6 @@
 int funcb();
 int funcc();
 
-int main() {
+int main(void) {
     return funca() + funcb() + funcc();
 }
diff --git a/test cases/common/53 custom target chain/usetarget/myexe.c b/test cases/common/53 custom target chain/usetarget/myexe.c
index a5a13c3..3331133 100644
--- a/test cases/common/53 custom target chain/usetarget/myexe.c
+++ b/test cases/common/53 custom target chain/usetarget/myexe.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("I am myexe.\n");
     return 0;
 }
diff --git a/test cases/common/55 object generator/prog.c b/test cases/common/55 object generator/prog.c
index 09f2790..dc468ec 100644
--- a/test cases/common/55 object generator/prog.c
+++ b/test cases/common/55 object generator/prog.c
@@ -2,6 +2,6 @@
 int func2_in_obj();
 int func3_in_obj();
 
-int main() {
+int main(void) {
     return func1_in_obj() + func2_in_obj() + func3_in_obj();
 }
diff --git a/test cases/common/56 install script/prog.c b/test cases/common/56 install script/prog.c
index 1d32c26..3bbf08e 100644
--- a/test cases/common/56 install script/prog.c
+++ b/test cases/common/56 install script/prog.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("This is text.\n");
     return 0;
 }
diff --git a/test cases/common/57 custom target source output/main.c b/test cases/common/57 custom target source output/main.c
index ca9909b..bca1387 100644
--- a/test cases/common/57 custom target source output/main.c
+++ b/test cases/common/57 custom target source output/main.c
@@ -1,5 +1,5 @@
 #include"mylib.h"
 
-int main() {
+int main(void) {
     return func();
 }
diff --git a/test cases/common/58 exe static shared/prog.c b/test cases/common/58 exe static shared/prog.c
index b1dbe14..3ba9a8f 100644
--- a/test cases/common/58 exe static shared/prog.c
+++ b/test cases/common/58 exe static shared/prog.c
@@ -1,7 +1,7 @@
 int shlibfunc2();
 int statlibfunc();
 
-int main() {
+int main(void) {
     if (statlibfunc() != 42)
         return 1;
     if (shlibfunc2() != 24)
diff --git a/test cases/common/6 linkshared/main.c b/test cases/common/6 linkshared/main.c
index ff5a732..81320e5 100644
--- a/test cases/common/6 linkshared/main.c
+++ b/test cases/common/6 linkshared/main.c
@@ -6,6 +6,6 @@
 
 int DLL_IMPORT func();
 
-int main() {
+int main(void) {
     return func();
 }
diff --git a/test cases/common/60 custom header generator/prog.c b/test cases/common/60 custom header generator/prog.c
index 2d071af..acd0ff7 100644
--- a/test cases/common/60 custom header generator/prog.c
+++ b/test cases/common/60 custom header generator/prog.c
@@ -1,5 +1,5 @@
 #include"myheader.lh"
 
-int main() {
+int main(void) {
     return RET_VAL;
 }
diff --git a/test cases/common/63 foreach/prog1.c b/test cases/common/63 foreach/prog1.c
index 30c67df..339dc49 100644
--- a/test cases/common/63 foreach/prog1.c
+++ b/test cases/common/63 foreach/prog1.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("This is test #1.\n");
     return 0;
 }
diff --git a/test cases/common/63 foreach/prog2.c b/test cases/common/63 foreach/prog2.c
index c25a205..c213288 100644
--- a/test cases/common/63 foreach/prog2.c
+++ b/test cases/common/63 foreach/prog2.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("This is test #2.\n");
     return 0;
 }
diff --git a/test cases/common/63 foreach/prog3.c b/test cases/common/63 foreach/prog3.c
index 7bea76d..905a530 100644
--- a/test cases/common/63 foreach/prog3.c
+++ b/test cases/common/63 foreach/prog3.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("This is test #3.\n");
     return 0;
 }
diff --git a/test cases/common/68 build always/main.c b/test cases/common/68 build always/main.c
index 3632ab8..a9ee55e 100644
--- a/test cases/common/68 build always/main.c
+++ b/test cases/common/68 build always/main.c
@@ -1,7 +1,7 @@
 #include<stdio.h>
 #include"version.h"
 
-int main() {
+int main(void) {
     printf("Version is %s.\n", version_string);
     return 0;
 }
diff --git a/test cases/common/69 vcstag/tagprog.c b/test cases/common/69 vcstag/tagprog.c
index 1c47e52..19b7754 100644
--- a/test cases/common/69 vcstag/tagprog.c
+++ b/test cases/common/69 vcstag/tagprog.c
@@ -2,7 +2,7 @@
 
 const char *vcstag;
 
-int main() {
+int main(void) {
     printf("Version is %s\n", vcstag);
     return 0;
 }
diff --git a/test cases/common/71 should fail/failing.c b/test cases/common/71 should fail/failing.c
index 6346e2d..3e70e50 100644
--- a/test cases/common/71 should fail/failing.c
+++ b/test cases/common/71 should fail/failing.c
@@ -1,3 +1,3 @@
-int main() {
+int main(void) {
     return 1;
 }
diff --git a/test cases/common/75 shared subproject/a.c b/test cases/common/75 shared subproject/a.c
index db85d41..5b1208d 100644
--- a/test cases/common/75 shared subproject/a.c
+++ b/test cases/common/75 shared subproject/a.c
@@ -2,7 +2,7 @@
 char func_b();
 char func_c();
 
-int main() {
+int main(void) {
     if(func_b() != 'b') {
         return 1;
     }
diff --git a/test cases/common/76 shared subproject 2/a.c b/test cases/common/76 shared subproject 2/a.c
index db85d41..5b1208d 100644
--- a/test cases/common/76 shared subproject 2/a.c
+++ b/test cases/common/76 shared subproject 2/a.c
@@ -2,7 +2,7 @@
 char func_b();
 char func_c();
 
-int main() {
+int main(void) {
     if(func_b() != 'b') {
         return 1;
     }
diff --git a/test cases/common/77 file object/prog.c b/test cases/common/77 file object/prog.c
index c2b6e98..e4a786c 100644
--- a/test cases/common/77 file object/prog.c
+++ b/test cases/common/77 file object/prog.c
@@ -2,7 +2,7 @@
 
 int func(); /* Files in different subdirs return different values. */
 
-int main() {
+int main(void) {
     if(func() == 0) {
         printf("Iz success.\n");
     } else {
diff --git a/test cases/common/77 file object/subdir1/prog.c b/test cases/common/77 file object/subdir1/prog.c
index cba4b14..1a09f7f 100644
--- a/test cases/common/77 file object/subdir1/prog.c
+++ b/test cases/common/77 file object/subdir1/prog.c
@@ -2,7 +2,7 @@
 
 int func();
 
-int main() {
+int main(void) {
     if(func() == 1) {
         printf("Iz success.\n");
     } else {
diff --git a/test cases/common/77 file object/subdir2/prog.c b/test cases/common/77 file object/subdir2/prog.c
index 124c98b..558e5ee 100644
--- a/test cases/common/77 file object/subdir2/prog.c
+++ b/test cases/common/77 file object/subdir2/prog.c
@@ -2,7 +2,7 @@
 
 int func();
 
-int main() {
+int main(void) {
     if(func() == 2) {
         printf("Iz success.\n");
     } else {
diff --git a/test cases/common/78 custom subproject dir/a.c b/test cases/common/78 custom subproject dir/a.c
index db85d41..5b1208d 100644
--- a/test cases/common/78 custom subproject dir/a.c
+++ b/test cases/common/78 custom subproject dir/a.c
@@ -2,7 +2,7 @@
 char func_b();
 char func_c();
 
-int main() {
+int main(void) {
     if(func_b() != 'b') {
         return 1;
     }
diff --git a/test cases/common/8 install/prog.c b/test cases/common/8 install/prog.c
index 33c14ce..9b6bdc2 100644
--- a/test cases/common/8 install/prog.c
+++ b/test cases/common/8 install/prog.c
@@ -1,3 +1,3 @@
-int main() {
+int main(void) {
     return 0;
 }
diff --git a/test cases/common/80 extract from nested subdir/tst/first/exe_first.c b/test cases/common/80 extract from nested subdir/tst/first/exe_first.c
index f6c1f74..e8188cd 100644
--- a/test cases/common/80 extract from nested subdir/tst/first/exe_first.c
+++ b/test cases/common/80 extract from nested subdir/tst/first/exe_first.c
@@ -1,5 +1,5 @@
 int first(void);
 
-int main() {
+int main(void) {
     return first() - 1001;
 }
diff --git a/test cases/common/81 internal dependency/src/main.c b/test cases/common/81 internal dependency/src/main.c
index 137cc61..dbb7c4a 100644
--- a/test cases/common/81 internal dependency/src/main.c
+++ b/test cases/common/81 internal dependency/src/main.c
@@ -1,7 +1,7 @@
 #include<stdio.h>
 #include<proj1.h>
 
-int main() {
+int main(void) {
     printf("Now calling into library.\n");
     proj1_func1();
     proj1_func2();
diff --git a/test cases/common/82 same basename/exe1.c b/test cases/common/82 same basename/exe1.c
index 458fc84..7bd54d4 100644
--- a/test cases/common/82 same basename/exe1.c
+++ b/test cases/common/82 same basename/exe1.c
@@ -1,5 +1,5 @@
 int func();
 
-int main() {
+int main(void) {
     return func();
 }
diff --git a/test cases/common/82 same basename/exe2.c b/test cases/common/82 same basename/exe2.c
index 9dbb09d..6c47a9d 100644
--- a/test cases/common/82 same basename/exe2.c
+++ b/test cases/common/82 same basename/exe2.c
@@ -1,5 +1,5 @@
 int func();
 
-int main() {
+int main(void) {
     return func() == 1 ? 0 : 1;
 }
diff --git a/test cases/common/83 declare dep/main.c b/test cases/common/83 declare dep/main.c
index 3c37f81..62200c9 100644
--- a/test cases/common/83 declare dep/main.c
+++ b/test cases/common/83 declare dep/main.c
@@ -5,7 +5,7 @@
 #error "Entity use flag not used for compilation."
 #endif
 
-int main() {
+int main(void) {
     if(entity_func1() != 5) {
         printf("Error in func1.\n");
         return 1;
diff --git a/test cases/common/84 extract all/prog.c b/test cases/common/84 extract all/prog.c
index 48e7680..de0cc7f 100644
--- a/test cases/common/84 extract all/prog.c
+++ b/test cases/common/84 extract all/prog.c
@@ -1,7 +1,7 @@
 #include"extractor.h"
 #include<stdio.h>
 
-int main() {
+int main(void) {
     if((1+2+3+4) != (func1() + func2() + func3() + func4())) {
         printf("Arithmetic is fail.\n");
         return 1;
diff --git a/test cases/common/85 add language/prog.c b/test cases/common/85 add language/prog.c
index bdd43ff..9d747f0 100644
--- a/test cases/common/85 add language/prog.c
+++ b/test cases/common/85 add language/prog.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("I am plain C.\n");
     return 0;
 }
diff --git a/test cases/common/86 identical target name in subproject/bar.c b/test cases/common/86 identical target name in subproject/bar.c
index cc34d94..f1bd822 100644
--- a/test cases/common/86 identical target name in subproject/bar.c
+++ b/test cases/common/86 identical target name in subproject/bar.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("I'm a main project bar.\n");
     return 0;
 }
diff --git a/test cases/common/86 identical target name in subproject/subprojects/foo/bar.c b/test cases/common/86 identical target name in subproject/subprojects/foo/bar.c
index 6e72576..5e7006b 100644
--- a/test cases/common/86 identical target name in subproject/subprojects/foo/bar.c
+++ b/test cases/common/86 identical target name in subproject/subprojects/foo/bar.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("I'm a subproject bar.\n");
     return 0;
 }
diff --git a/test cases/common/89 private include/user/libuser.c b/test cases/common/89 private include/user/libuser.c
index b72bb4d..c172486 100644
--- a/test cases/common/89 private include/user/libuser.c
+++ b/test cases/common/89 private include/user/libuser.c
@@ -1,6 +1,6 @@
 #include"foo1.h"
 #include"foo2.h"
 
-int main() {
+int main(void) {
     return foo1() + foo2();
 }
diff --git a/test cases/common/94 gen extra/plain.c b/test cases/common/94 gen extra/plain.c
index 914de72..6fc3d22 100644
--- a/test cases/common/94 gen extra/plain.c
+++ b/test cases/common/94 gen extra/plain.c
@@ -1,5 +1,5 @@
 int bob_mcbob();
 
-int main() {
+int main(void) {
     return bob_mcbob();
 }
diff --git a/test cases/common/94 gen extra/upper.c b/test cases/common/94 gen extra/upper.c
index dad78fc..f216dce 100644
--- a/test cases/common/94 gen extra/upper.c
+++ b/test cases/common/94 gen extra/upper.c
@@ -1,5 +1,5 @@
 int BOB_MCBOB();
 
-int main() {
+int main(void) {
     return BOB_MCBOB();
 }
diff --git a/test cases/common/95 benchmark/delayer.c b/test cases/common/95 benchmark/delayer.c
index c8da7ae..b410c46 100644
--- a/test cases/common/95 benchmark/delayer.c
+++ b/test cases/common/95 benchmark/delayer.c
@@ -6,7 +6,7 @@
 #include<windows.h>
 #endif
 
-int main() {
+int main(void) {
     srand(time(NULL));
 #if !defined(_WIN32)
     struct timespec t;
diff --git a/test cases/common/96 test workdir/opener.c b/test cases/common/96 test workdir/opener.c
index 7be914d..c946e18 100644
--- a/test cases/common/96 test workdir/opener.c
+++ b/test cases/common/96 test workdir/opener.c
@@ -2,7 +2,7 @@
 
 #include<stdio.h>
 
-int main() {
+int main(void) {
     FILE *f = fopen("opener.c", "r");
     if(f) {
         fclose(f);
diff --git a/test cases/common/97 suites/exe1.c b/test cases/common/97 suites/exe1.c
index 89a1c4e..6e32362 100644
--- a/test cases/common/97 suites/exe1.c
+++ b/test cases/common/97 suites/exe1.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("I am test exe1.\n");
     return 0;
 }
diff --git a/test cases/common/97 suites/exe2.c b/test cases/common/97 suites/exe2.c
index 92f287d..21a9dd6 100644
--- a/test cases/common/97 suites/exe2.c
+++ b/test cases/common/97 suites/exe2.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("I am test exe2.\n");
     return 0;
 }
diff --git a/test cases/common/97 suites/subprojects/sub/sub1.c b/test cases/common/97 suites/subprojects/sub/sub1.c
index ab5822a..e067624 100644
--- a/test cases/common/97 suites/subprojects/sub/sub1.c
+++ b/test cases/common/97 suites/subprojects/sub/sub1.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("I am test sub1.\n");
     return 0;
 }
diff --git a/test cases/common/97 suites/subprojects/sub/sub2.c b/test cases/common/97 suites/subprojects/sub/sub2.c
index f1e6d78..0b457dc 100644
--- a/test cases/common/97 suites/subprojects/sub/sub2.c
+++ b/test cases/common/97 suites/subprojects/sub/sub2.c
@@ -1,6 +1,6 @@
 #include<stdio.h>
 
-int main() {
+int main(void) {
     printf("I am test sub2.\n");
     return 0;
 }
diff --git a/test cases/common/98 threads/threadprog.c b/test cases/common/98 threads/threadprog.c
index 5db40f1..789f24b 100644
--- a/test cases/common/98 threads/threadprog.c
+++ b/test cases/common/98 threads/threadprog.c
@@ -8,7 +8,7 @@
     return 0;
 }
 
-int main() {
+int main(void) {
     DWORD id;
     HANDLE th;
     printf("Starting thread.\n");
@@ -27,7 +27,7 @@
     return NULL;
 }
 
-int main() {
+int main(void) {
     pthread_t thread;
     int rc;
     printf("Starting thread.\n");
diff --git a/test cases/common/99 manygen/depuser.c b/test cases/common/99 manygen/depuser.c
index 6374cd0..1ab2487 100644
--- a/test cases/common/99 manygen/depuser.c
+++ b/test cases/common/99 manygen/depuser.c
@@ -1,6 +1,6 @@
 #include"gen_func.h"
 
-int main() {
+int main(void) {
     unsigned int i = (unsigned int) gen_func_in_lib();
     unsigned int j = (unsigned int) gen_func_in_obj();
     unsigned int k = (unsigned int) gen_func_in_src();