From 5594594e1604ff2db34e9844be206c6ae17d3838 Mon Sep 17 00:00:00 2001
From: Marcus Comstedt <marcus@mc.pp.se>
Date: Tue, 27 Oct 2020 14:04:28 +0100
Subject: [PATCH] Prevent CXXFLAGS from leaking to abc Makefile

This fixes an issue with abc/depends.sh when the compiler is clang.
---
 Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Makefile b/Makefile
index 88a9f35f4..0fb3ef150 100644
--- a/Makefile
+++ b/Makefile
@@ -661,6 +661,10 @@ ifeq ($(LINK_ABC),1)
 OBJS += $(PROGRAM_PREFIX)yosys-libabc.a
 endif
 
+# prevent the CXXFLAGS set by this Makefile from reaching abc/Makefile,
+# especially the -MD flag which will break the build when CXX is clang
+unexport CXXFLAGS
+
 top-all: $(TARGETS) $(EXTRA_TARGETS)
 	@echo ""
 	@echo "  Build successful."
-- 
2.30.2