From: Julian Ospald <hasufell@gentoo.org>
Date: Wed Oct 24 15:41:33 UTC 2012
Subject: build system

don't overwrite system CFLAGS, only append "-g -Os" if DEBUG=1 is passed
as argument

--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,11 @@
-CFLAGS := -g -Os
+CC ?= gcc
+
+# set to 1 to enable debug flags
+DEBUG = 0
+ifeq ($(DEBUG),1)
+CFLAGS += -g -Os
+endif
+
 prefix := /usr
 etcprefix :=
 MANDIR := ${prefix}/share/man