Index: autotools/ac_c_compile_flags.m4
--- autotools/ac_c_compile_flags.m4.orig
+++ autotools/ac_c_compile_flags.m4
@@ -5,7 +5,6 @@ do
  AC_MSG_CHECKING(whether compiler supports $ac_flag)
  CFLAGS="$NEW_CFLAGS $ac_flag"
  AC_TRY_COMPILE(,[
-  void f() {};
  ],[
   NEW_CFLAGS="$CFLAGS"
   AC_MSG_RESULT(yes)
