--- Makefile.defs--	2008-12-26 22:58:25.000000000 +0530
+++ Makefile.defs	2008-12-26 22:59:01.000000000 +0530
@@ -8,9 +8,9 @@
 
 # Installation options
 # PREFIX is only used here.
-PREFIX   = /usr/local
-ELISPDIR = $(PREFIX)/share/emacs/site-lisp/remember
-INFODIR  = $(PREFIX)/info
+PREFIX   ?= /usr/local
+ELISPDIR ?= $(PREFIX)/share/emacs/site-lisp/remember
+INFODIR  ?= $(PREFIX)/info
 
 # Command to use to install the Info dir entry
 INSTALLINFO = install-info --info-dir=$(INFODIR)