Add patch to fix gcc-4.8.5.

(at least cross/bossa, bossa-20140109nb2, has a problem)
cross/bossa/work/.buildlink/include/wx-2.8/wx/debug.h:194:43: error:
 typedef 'wxDummyCheckInt' locally defined but not used [-Werror=unused-local-typedefs]

x11/wxGTK28/distinfo

@@ -1,4 +1,4 @@
-$NetBSD: distinfo,v 1.17 2015/11/04 03:28:56 agc Exp $
+$NetBSD: distinfo,v 1.18 2015/11/22 22:16:04 mef Exp $
 
 SHA1 (wxGTK-2.8.12-libtool.diff.bz2) = f2c9b8a06c08101325ffe09ad77f4800f7aa8730
 RMD160 (wxGTK-2.8.12-libtool.diff.bz2) = 05b763aa44a8e8c8ad565af2a188d7c6437f2133
@@ -11,3 +11,4 @@ Size (wxGTK-2.8.12.tar.bz2) = 9292767 bytes
 SHA1 (patch-aa) = ad2fcc73ffe0db67cb9ef5fe87fb1248f7b7675c
 SHA1 (patch-ab) = 6f6278ec6b92a39abe29ec09053cd7007cd32fef
 SHA1 (patch-ac) = 50cf253797f2dee8b9dab08d138d0070e25e7a8c
+SHA1 (patch-include_wx_debug.h) = bc25a486361194d8d70c69bcd833e085fbcbdec3

x11/wxGTK28/patches/patch-include_wx_debug.h

@@ -0,0 +1,18 @@
+$NetBSD: patch-include_wx_debug.h,v 1.1 2015/11/22 22:16:04 mef Exp $
+
+with gcc-4.8.5:
+(at least cross/bossa, bossa-20140109nb2, has a problem)
+cross/bossa/work/.buildlink/include/wx-2.8/wx/debug.h:194:43: error: 
+	typedef 'wxDummyCheckInt' locally defined but not used [-Werror=unused-local-typedefs]
+
+--- include/wx/debug.h.orig	2011-03-22 21:16:46.000000000 +0900
++++ include/wx/debug.h	2015-11-22 22:18:12.000000000 +0900
+@@ -191,7 +191,7 @@
+ /*  as wxCHECK2 but with a message explaining why we fail */
+ 
+ #ifdef __GNUC__
+-    #define wxFORCE_SEMICOLON typedef int wxDummyCheckInt
++    #define wxFORCE_SEMICOLON typedef int wxDummyCheckInt __attribute__((unused))
+     /* Note: old gcc versions (e.g. 2.8) give an internal compiler error */
+     /*     on a simple forward declaration, when used in a template    */
+     /*     function, so rather use a dummy typedef which does work...  */