--- Makefile.ori	2016-04-10 22:34:31.976222662 +0200
+++ Makefile	2016-04-10 22:37:49.636225327 +0200
@@ -1,8 +1,8 @@
-CC = gcc
-CFLAGS = -Wall
-DEBUG = -g
+CC ?= gcc
+CFLAGS ?= -Wall
+DEBUG ?= -g
 LIBS = -lm
-OPT = -O3
+#OPT = -O3
 export MAXKMERLENGTH = 64
 export CATEGORIES = 2
 DEF = -D MAXKMERLENGTH=$(MAXKMERLENGTH) -D CATEGORIES=$(CATEGORIES)