diff --git a/src/pl/plperl/GNUmakefile b/src/pl/plperl/GNUmakefile
index a51f0c2429..7e700a7a34 100644
--- a/src/pl/plperl/GNUmakefile
+++ b/src/pl/plperl/GNUmakefile
@@ -1,4 +1,4 @@
-# $Header: /cvsroot/pgsql/src/pl/plperl/GNUmakefile,v 1.5 2000/10/24 17:01:05 tgl Exp $
+# $Header: /cvsroot/pgsql/src/pl/plperl/GNUmakefile,v 1.6 2000/11/02 18:40:13 petere Exp $
 
 subdir = src/pl/plperl
 top_builddir = ../../..
@@ -11,9 +11,9 @@ all: Makefile
 	$(MAKE) -f $< all
 
 Makefile: Makefile.PL
-	@plperl_installdir='$(plperl_installdir)' \
-	  EXTRA_INCLUDES='-I$(top_srcdir)/src/include $(INCLUDES)' \
-	  $(PERL) $<
+	plperl_installdir='$(plperl_installdir)' \
+	EXTRA_INCLUDES='$(filter -I%, $(CPPFLAGS))' \
+	$(PERL) $<
 
 install: all installdirs
 	$(MAKE) -f Makefile install