diff --git a/source3/lib/util_sec.c b/source3/lib/util_sec.c
index 94082697def..1eac7d711b8 100644
--- a/source3/lib/util_sec.c
+++ b/source3/lib/util_sec.c
@@ -549,7 +549,7 @@ static int have_syscall(void)
 	return 0;
 }
 
-main()
+int main(void)
 {
         if (getuid() != 0) {
 #if (defined(AIX) && defined(USE_SETREUID))