--- a/contrib/php/build/rules.mk
+++ b/contrib/php/build/rules.mk
@@ -63,10 +63,10 @@
 
 install-modules:
 	@test -d modules && \
-	$(mkinstalldirs) $(moduledir) && \
-	echo "installing shared modules into $(moduledir)" && \
+	$(mkinstalldirs) $(DESTDIR)$(moduledir) && \
+	echo "installing shared modules into $(DESTDIR)$(moduledir)" && \
 	rm -f modules/*.la && \
-	cp modules/* $(moduledir) || true
+	cp modules/* $(DESTDIR)$(moduledir) || true
 
 include $(builddir)/.deps