disas: Add capstone as submodule

Do not require the submodule, but use it if present.  Allow the
command-line to override system or git submodule either way.

Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
diff --git a/configure b/configure
index d06ad64..23eddc2 100755
--- a/configure
+++ b/configure
@@ -1299,6 +1299,10 @@
   ;;
   --enable-capstone) capstone="yes"
   ;;
+  --enable-capstone=git) capstone="git"
+  ;;
+  --enable-capstone=system) capstone="system"
+  ;;
   *)
       echo "ERROR: unknown option $opt"
       echo "Try '$0 --help' for more information"
@@ -4419,18 +4423,54 @@
 ##########################################
 # capstone
 
-if test "$capstone" != no; then
-  if $pkg_config capstone; then
-    capstone=yes
+case "$capstone" in
+  "" | yes)
+    if $pkg_config capstone; then
+      capstone=system
+    elif test -e "${source_path}/.git" ; then
+      capstone=git
+    elif test -e "${source_path}/capstone/Makefile" ; then
+      capstone=internal
+    elif test -z "$capstone" ; then
+      capstone=no
+    else
+      feature_not_found "capstone" "Install capstone devel or git submodule"
+    fi
+    ;;
+
+  system)
+    if ! $pkg_config capstone; then
+      feature_not_found "capstone" "Install capstone devel"
+    fi
+    ;;
+esac
+
+case "$capstone" in
+  git | internal)
+    if test "$capstone" = git; then
+      git_submodules="${git_submodules} capstone"
+    fi
+    mkdir -p capstone
+    QEMU_CFLAGS="$QEMU_CFLAGS -I\$(SRC_PATH)/capstone/include"
+    if test "$mingw32" = "yes"; then
+      LIBCAPSTONE=capstone.lib
+    else
+      LIBCAPSTONE=libcapstone.a
+    fi
+    LIBS="-L\$(BUILD_DIR)/capstone -lcapstone $LIBS"
+    ;;
+
+  system)
     QEMU_CFLAGS="$QEMU_CFLAGS $($pkg_config --cflags capstone)"
     LIBS="$($pkg_config --libs capstone) $LIBS"
-  else
-    if test "$capstone" = yes; then
-      feature_not_found capstone
-    fi
-    capstone=no
-  fi
-fi
+    ;;
+
+  no)
+    ;;
+  *)
+    error_exit "Unknown state for capstone: $capstone"
+    ;;
+esac
 
 ##########################################
 # check if we have fdatasync
@@ -6165,7 +6205,7 @@
 if test "$ivshmem" = "yes" ; then
   echo "CONFIG_IVSHMEM=y" >> $config_host_mak
 fi
-if test "$capstone" = "yes" ; then
+if test "$capstone" != "no" ; then
   echo "CONFIG_CAPSTONE=y" >> $config_host_mak
 fi
 
@@ -6650,6 +6690,12 @@
 if [ "$dtc_internal" = "yes" ]; then
   echo "config-host.h: subdir-dtc" >> $config_host_mak
 fi
+if [ "$capstone" = "git" -o "$capstone" = "internal" ]; then
+  echo "config-host.h: subdir-capstone" >> $config_host_mak
+fi
+if test -n "$LIBCAPSTONE"; then
+  echo "LIBCAPSTONE=$LIBCAPSTONE" >> $config_host_mak
+fi
 
 if test "$numa" = "yes"; then
   echo "CONFIG_NUMA=y" >> $config_host_mak