$OpenBSD: patch-w_intersect_c,v 1.4 2017/02/01 10:09:58 kirby Exp $
--- src/w_intersect.c.orig	Sun Jul 24 00:10:28 2016
+++ src/w_intersect.c	Thu Dec 22 12:22:20 2016
@@ -26,7 +26,9 @@
 #include "w_msgpanel.h"
 #include "f_util.h"
 #include "u_quartic.h"
+#if !defined(__FreeBSD__) && !defined(__OpenBSD__)
 #include <alloca.h>
+#endif
 #include <math.h>
 #undef I
 
