implementations of dup3 and fallocate that are good enough to fool LTP

updated fallocate check to new configure, added dup3 check as suggested
by Jan-Simon Möller.

Riku: updated to apply to current git.

Signed-off-by: Ulrich Hecht <uli@suse.de>
Signed-off-by: Riku Voipio <riku.voipio@iki.fi>
diff --git a/configure b/configure
index ca6d45c..3df9d07 100755
--- a/configure
+++ b/configure
@@ -1569,6 +1569,36 @@
   eventfd=yes
 fi
 
+# check for fallocate
+fallocate=no
+cat > $TMPC << EOF
+#include <fcntl.h>
+
+int main(void)
+{
+    fallocate(0, 0, 0, 0);
+    return 0;
+}
+EOF
+if $cc $ARCH_CFLAGS -o $TMPE $TMPC 2> /dev/null ; then
+  fallocate=yes
+fi
+
+# check for dup3
+dup3=no
+cat > $TMPC << EOF
+#include <unistd.h>
+
+int main(void)
+{
+    dup3(0, 0, 0);
+    return 0;
+}
+EOF
+if $cc $ARCH_CFLAGS -o $TMPE $TMPC 2> /dev/null ; then
+  dup3=yes
+fi
+
 # Check if tools are available to build documentation.
 if test "$docs" != "no" ; then
   if test -x "`which texi2html 2>/dev/null`" -a \
@@ -1950,6 +1980,12 @@
 if test "$eventfd" = "yes" ; then
   echo "CONFIG_EVENTFD=y" >> $config_host_mak
 fi
+if test "$fallocate" = "yes" ; then
+  echo "CONFIG_FALLOCATE=y" >> $config_host_mak
+fi
+if test "$dup3" = "yes" ; then
+  echo "CONFIG_DUP3=y" >> $config_host_mak
+fi
 if test "$inotify" = "yes" ; then
   echo "CONFIG_INOTIFY=y" >> $config_host_mak
 fi