pkg/52562: [patch] databases/gnats: fix FTBFS on OpenIndiana

[mcy%lm7.fr@localhost]

>Number:         52562
>Category:       pkg
>Synopsis:       [patch] databases/gnats: fix FTBFS on OpenIndiana
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Sep 20 15:40:00 +0000 2017
>Originator:     Matteo Cypriani
>Release:        SunOS 5.11
>Environment:
System: SunOS indiana 5.11 illumos-919f1431f0 i86pc i386 i86pc
Architecture: i86pc
>Description:
The attached patch fixes a double #define that occurs (at least) on
OpenIndiana.
>How-To-Repeat:
>Fix:
$NetBSD$

Fixes possible multiple definitions of __EXTENSIONS__.
--- gnats/config.h~	dim. avr. 15 14:11:51 2001
+++ gnats/config.h	mar. sept. 19 14:19:57 2017
@@ -6,7 +6,9 @@
 #define _GNU_SOURCE
 #endif
 
+#ifndef __EXTENSIONS__
 #define __EXTENSIONS__
+#endif
 
 /* Include the autoconf-generated configuration header. */
 #include "autoconf.h"