https://bugs.gentoo.org/881693
--- a/configure.ac
+++ b/configure.ac
@@ -446,8 +446,9 @@ fi
 ###
 ### See in what direction the stack grows (code stolen from Sawfish)
 ###
-AC_RUN_IFELSE([AC_LANG_SOURCE([[ void inner (char *foo) { char bar; exit (!(foo >= &bar)); }
-             void main () { char foo; inner (&foo); } ]])],[STACK_DIRECTION="DOWN"],[STACK_DIRECTION="UP"],[echo "Stack direction is not detected when cross compiling for now"])
+AC_RUN_IFELSE([AC_LANG_SOURCE([[#include <stdlib.h>
+             void inner (char *foo) { char bar; exit (!(foo >= &bar)); }
+             int main (void) { char foo; inner (&foo); } ]])],[STACK_DIRECTION="DOWN"],[STACK_DIRECTION="UP"],[echo "Stack direction is not detected when cross compiling for now"])