iproute2 - Split up cflags

Allows setting optimisation flags at compile time without patching the Makefile.

modified:   Makefile

Signed-off-by: Christoph J. Thompson <cjsthompson@gmail.com>
diff --git a/Makefile b/Makefile
index a2810e5..7e7459b 100644
--- a/Makefile
+++ b/Makefile
@@ -29,8 +29,10 @@
 
 CC = gcc
 HOSTCC = gcc
-CCOPTS = -D_GNU_SOURCE -O2 -Wstrict-prototypes -Wall
-CFLAGS = $(CCOPTS) -I../include $(DEFINES)
+DEFINES += -D_GNU_SOURCE
+CCOPTS = -O2
+WFLAGS = -Wall -Wstrict-prototypes
+CFLAGS = $(WFLAGS) $(CCOPTS) -I../include $(DEFINES)
 YACCFLAGS = -d -t -v
 
 SUBDIRS=lib ip tc misc netem genl