diff --git a/Makefile b/Makefile
index f24246528f..2a219ee2a6 100644
--- a/Makefile
+++ b/Makefile
@@ -32,6 +32,8 @@ REGRESS = security rum rum_validate rum_hash ruminv timestamp orderby orderby_ha
     macaddr inet cidr text varchar char bytea bit varbit \
 	numeric rum_weight expr
 
+undefine REGRESS
+
 TAP_TESTS = 1
 
 ifdef USE_PGXS