--- makefile.orig	2013-04-12 16:31:19 UTC
+++ makefile
@@ -1,5 +1,5 @@
 LIBNAME = lpeg
-LUADIR = /usr/include/lua5.1/
+LUADIR ?= /usr/include/lua5.1/
 
 COPT = -O2
 # COPT = -DLPEG_DEBUG -g
@@ -22,8 +22,8 @@ CWARNS = -Wall -Wextra -pedantic \
 # -Wunreachable-code \
 
 
-CFLAGS = $(CWARNS) $(COPT) -ansi -I$(LUADIR) -fPIC
-CC = gcc
+CFLAGS += $(CWARNS) $(COPT) -ansi -I$(LUADIR) -fPIC
+CC ?= gcc
 
 FILES = lpvm.o lpcap.o lptree.o lpcode.o lpprint.o