From 716e5c49e9ff4a63f6bfb441105cb463d5019b19 Mon Sep 17 00:00:00 2001
From: John Marino <marino@FreeBSD.org>
Date: Wed, 18 Mar 2015 10:39:04 +0000
Subject: [PATCH] lang/gcc5: Support DragonFly's gcc50 base compiler in
 specific scenario

---
 lang/gcc5/Makefile.DragonFly | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/lang/gcc5/Makefile.DragonFly b/lang/gcc5/Makefile.DragonFly
index 78bc57da0ad5..5342d32b33f5 100644
--- a/lang/gcc5/Makefile.DragonFly
+++ b/lang/gcc5/Makefile.DragonFly
@@ -1,3 +1,11 @@
 # $FreeBSD$
 
 OPTIONS_EXCLUDE= JAVA
+
+# The following modification to CXXFLAGS is needed in the case of DragonFly
+# 4.1+ building lang/gcc5 with the gcc50 base compiler when the system
+# libraries were built by the gcc47 base compiler.  The sys.mk file
+# automatically adds -D_GLIBCXX_USE_CXX11_ABI=0 to CXXFLAGS in that case,
+# which will break the build.
+
+CXXFLAGS:=	${CXXFLAGS:N-D_GLIBCXX_USE_CXX11_ABI*}