From ba86521396e25a9e03bb21e3205e8b0e57f0410c Mon Sep 17 00:00:00 2001
From: Ed Maste <emaste@FreeBSD.org>
Date: Fri, 22 Jan 2016 02:28:17 +0000
Subject: [PATCH] Remove old generated unwind.h when using LLVM libunwind

When not using LLVM libunwind, unwind.h is a generated header and a stale
copy may remain in the OBJDIR after enabling LLVM libunwind. Explicitly
remove it.

Reported by:	bz
Reviewed by:	bdrewery
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D5019
---
 gnu/lib/libgcc/Makefile | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/gnu/lib/libgcc/Makefile b/gnu/lib/libgcc/Makefile
index ec3c7f4185ff..f3166e78a9b5 100644
--- a/gnu/lib/libgcc/Makefile
+++ b/gnu/lib/libgcc/Makefile
@@ -193,7 +193,12 @@ LIB2_DIVMOD_FUNCS:= ${LIB2_DIVMOD_FUNCS:S/${sym}//g}
 .endif
 
 COMMONHDRS=	tm.h tconfig.h options.h gthr-default.h
-.if ${MK_LLVM_LIBUNWIND} == no
+.if ${MK_LLVM_LIBUNWIND} != "no"
+# unwind.h is a generated file when MK_LLVM_LIBUNWIND == "no", and a stale
+# copy may be left behind in OBJDIR when switching, so remove it explicitly.
+beforebuild:
+	@rm -f ${.OBJDIR}/unwind.h
+.else
 COMMONHDRS+=	unwind.h
 .endif