Prepend DESTDIR to paths for staged installs
diff --git a/Makefile.am b/Makefile.am
index fc4479f..36272f4 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -65,12 +65,12 @@
 
 if ENABLE_OLDNAME_COMPAT
 install-data-hook:
-	test \! -e "$(includedir)/json" || rm "$(includedir)/json"
-	$(LN_S) json-c "$(includedir)/json"
+	test \! -e "$(DESTDIR)@includedir@json" || rm "$(DESTDIR)@includedir@/json"
+	$(LN_S) json-c "$(DESTDIR)@includedir@/json"
 
 uninstall-local:
-	rm -f "$(includedir)/json"
-	rm -rf "$(includedir)/json-c"
+	rm -f "$(DESTDIR)@includedir@/json"
+	rm -rf "$(DESTDIR)@includedir@/json-c"
 
 endif