diff --git Makefile Makefile
index 2bac7c1..a643ccf 100644
--- Makefile
+++ Makefile
@@ -1,5 +1,5 @@
-CC		:= gcc
-FLAGS	:= --std=c99 -Wall -O3
+CC		?= gcc
+FLAGS	        += $(CFLAGS) --std=c99 -Wall
 SRC		:= src
 BIN		:= bin
 BUILD	:= .build