$OpenBSD: patch-configure_ac,v 1.1 2017/09/25 09:16:12 robert Exp $

Index: configure.ac
--- configure.ac.orig
+++ configure.ac
@@ -233,7 +233,7 @@ case "$host" in
     SAVED_CFLAGS="${CFLAGS}"
     CFLAGS="-fvisibility=hidden"
     AC_MSG_CHECKING([for -fvisibility=hidden compiler flag])
-    AC_TRY_COMPILE([], [int main (void) { return 0; }],
+    AC_TRY_COMPILE([], [],
                    AC_MSG_RESULT(yes)
                    enable_fvisibility_hidden=yes,
                    AC_MSG_RESULT(no)
