diff --git a/make/proj.mk b/make/proj.mk
index 5635db8e..a44cebbc 100644
--- a/make/proj.mk
+++ b/make/proj.mk
@@ -4,7 +4,7 @@
 # $Id$
 
 PROJECT         = jw-build
-MODDIR          = $(TOPDIR)
+MODDIR         ?= $(TOPDIR)
 JANWARE_WIKI    = priv
 
 REQUIRED = inst/pre \