$OpenBSD: patch-configure_ac,v 1.1 2017/09/27 16:33:21 dcoppa Exp $

Index: configure.ac
--- configure.ac.orig
+++ configure.ac
@@ -167,9 +167,10 @@ fi
 
 # when possible hide stuff we don't want to export
 AC_MSG_CHECKING(for visibility __attribute__)
-AC_TRY_COMPILE([], [
+AC_TRY_COMPILE([
    void __attribute__ ((visibility ("hidden"))) doit (void) {}
-   void main () { doit (); }
+], [
+   doit ();
 ], [
    have_visibility_hidden=yes
    AC_MSG_RESULT(yes)
