Add a patch allowing gforth to build on mips64el.

From Donovan Watteau on ports@, thx

lang/gforth/Makefile

@@ -1,6 +1,6 @@
-# $OpenBSD: Makefile,v 1.9 2012/06/04 21:02:15 pascal Exp $
+# $OpenBSD: Makefile,v 1.10 2012/10/14 20:18:56 landry Exp $
 
-ONLY_FOR_ARCHS =	amd64 i386 powerpc sparc sparc64
+ONLY_FOR_ARCHS =	amd64 i386 mips64el powerpc sparc sparc64
 
 COMMENT =		ANS Standard Forth interpreter and compiler
 

lang/gforth/patches/patch-arch_mips_machine_h

@@ -0,0 +1,18 @@
+$OpenBSD: patch-arch_mips_machine_h,v 1.1 2012/10/14 20:18:56 landry Exp $
+
+Let the MIPS backend build on OpenBSD.
+
+--- arch/mips/machine.h.orig	Sun Mar  9 16:06:31 2003
++++ arch/mips/machine.h	Wed Oct  3 20:28:31 2012
+@@ -31,8 +31,10 @@
+ #endif
+ 
+ /* cache flush stuff */
+-#ifdef ultrix
++#if defined(ultrix)
+ #include <mips/cachectl.h>
++#elif defined(__OpenBSD__)
++#include <mips64/sysarch.h>
+ #else
+ /* works on Irix */
+ #include <sys/cachectl.h>