--- a/Makefile
+++ b/Makefile
@@ -15,17 +15,17 @@ shared	= ${libname}.${VER}.so
 soname	= ${libname}.so.${MVER}
 
 # overwritten by caller (e.g.: debian/rules)
-basedir	= /usr/local
+basedir	?= /usr/local
 srcdir=.
 
 libdir	= ${basedir}/lib
 incdir	= ${basedir}/include
 mandir	= ${basedir}/share/man
 
-CC	= gcc
-LCFLAGS	= -g -O2 -fPIC -Wall -pipe -D_REENTRANT 
-CFLAGS	= -g
-LDLIBS	= -llockdev
+CC	?= gcc
+LCFLAGS	?= -g -O2 -fPIC -Wall -pipe -D_REENTRANT 
+CFLAGS	?= -g
+LDLIBS	?= -llockdev
 
 .PHONY: shared static perl-lib
 ALL:	shared static perl-lib