--- Makefile.orig
+++ Makefile
@@ -21,7 +21,8 @@
 include Makefile.cfg
 
-export CC = gcc -pthread
-export CFLAGS += -I. -Wall -Os -ggdb -D_GNU_SOURCE -fPIC
-export LDLIBS += -lncursesw
+export CC = gcc
+OPTFLAGS=-Os -ggdb
+export CFLAGS += -pthread -I. -Wall -D_GNU_SOURCE -fPIC $(OPTFLAGS)
+export LDLIBS += -pthread -lncursesw
 
 SONAME  := libstfl.so.0