From dea70e3fb1f6791c78f82fdd4793ef630b276efa Mon Sep 17 00:00:00 2001
From: Ivan Maidanski <ivmai@mail.ru>
Date: Fri, 9 Dec 2016 03:21:05 +0300
Subject: [PATCH] Support CFLAGS_EXTRA to pass extra user-defined compiler
 flags (configure)

* Makefile.am (CFLAGS, CXXFLAGS): Append $(CFLAGS_EXTRA).
* configure.ac: Add AC_SUBST(CFLAGS_EXTRA).
---
 Makefile.am  | 3 +++
 configure.ac | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/Makefile.am b/Makefile.am
index 03449aaf..175484be 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -128,6 +128,9 @@ EXTRA_DIST += gc_cpp.cpp
 AM_CXXFLAGS = @GC_CFLAGS@
 AM_CFLAGS = $(WERROR_CFLAGS) @GC_CFLAGS@
 
+CFLAGS += $(CFLAGS_EXTRA)
+CXXFLAGS += $(CFLAGS_EXTRA)
+
 ## FIXME: relies on internal code generated by automake.
 ## FIXME: ./configure --enable-dependency-tracking should be used
 #all_objs = @addobjs@ $(libgc_la_OBJECTS)
diff --git a/configure.ac b/configure.ac
index 1c4e2a4a..d675f21f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -90,6 +90,9 @@ esac
 GC_CFLAGS=${gc_cflags}
 AC_SUBST(GC_CFLAGS)
 
+# Extra user-defined flags to pass both to C and C++ compilers.
+AC_SUBST([CFLAGS_EXTRA])
+
 AC_ARG_ENABLE(threads,
   [AC_HELP_STRING([--enable-threads=TYPE], [choose threading package])],
   THREADS=$enableval,
-- 
2.40.0