From 0ff06b4ac38a3d53c32e52b2c649dd2d4b3d2b0c Mon Sep 17 00:00:00 2001
From: Ben Noordhuis <info@bnoordhuis.nl>
Date: Wed, 10 Apr 2013 23:40:55 +0200
Subject: [PATCH] build: -Wno-dollar-in-identifier-extension is clang only

Add a compiler check because turning on the option unconditionally
breaks the build when CC=gcc.

This should also fix the build on versions of OS X that predate Apple's
switch to clang (10.6 and older.)
---
 config-unix.mk | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/config-unix.mk b/config-unix.mk
index 50695d75..ae510a33 100644
--- a/config-unix.mk
+++ b/config-unix.mk
@@ -80,8 +80,12 @@ endif
 
 ifeq (darwin,$(PLATFORM))
 HAVE_DTRACE=1
-# dtrace(1) probes contain dollar signs.
+# dtrace(1) probes contain dollar signs on OS X. Mute the warnings they
+# generate but only when CC=clang, -Wno-dollar-in-identifier-extension
+# is a clang extension.
+ifeq (__clang__,$(shell sh -c "$(CC) -dM -E - </dev/null | grep -ow __clang__"))
 CFLAGS += -Wno-dollar-in-identifier-extension
+endif
 CPPFLAGS += -D_DARWIN_USE_64_BIT_INODE=1
 LDFLAGS += -framework Foundation \
            -framework CoreServices \