diff --git a/doc/src/sgml/Makefile b/doc/src/sgml/Makefile
index 2e6bda7cdb2c8869607625e7361368d966cbd711..666e798109ca6e7ea092954e4cfaa55b63ea6bfe 100644
--- a/doc/src/sgml/Makefile
+++ b/doc/src/sgml/Makefile
@@ -2,7 +2,7 @@
 #
 # PostgreSQL documentation makefile
 #
-# $PostgreSQL: pgsql/doc/src/sgml/Makefile,v 1.95 2007/02/09 15:55:57 petere Exp $
+# $PostgreSQL: pgsql/doc/src/sgml/Makefile,v 1.96 2007/02/09 20:40:13 neilc Exp $
 #
 #----------------------------------------------------------------------------
 
@@ -105,7 +105,7 @@ draft:
 	@$(MAKE) DRAFT="Y" html
 
 
-COLLATEINDEX = LC_ALL=C $(PERL) $(COLLATEINDEX) -f -g
+COLLATEINDEX := LC_ALL=C $(PERL) $(COLLATEINDEX) -f -g
 
 # bookindex.sgml is required so there is a proper index for all output formats
 bookindex.sgml: HTML.index