It seems like newer autoconf versions need code that is test compiled to be enclosed by a AC_LANG_SOURCE macro. Signed-off-by: Christoph Hellwig <hch at lst.de> Index: sheepdog/configure.ac =================================================================== --- sheepdog.orig/configure.ac 2012-05-10 16:34:09.183990201 +0200 +++ sheepdog/configure.ac 2012-05-10 16:34:13.471990160 +0200 @@ -142,7 +142,7 @@ AC_CONFIG_FILES([Makefile cc_supports_flag() { local CFLAGS="$@" AC_MSG_CHECKING([whether $CC supports "$@"]) - AC_COMPILE_IFELSE([int main(){return 0;}] , + AC_COMPILE_IFELSE([AC_LANG_SOURCE([int main(){return 0;}])] , [RC=0; AC_MSG_RESULT([yes])], [RC=1; AC_MSG_RESULT([no])]) return $RC |