--- a/Makefile	Sat Aug 30 01:51:02 2014 +0200
+++ b/Makefile	Tue Sep 02 11:28:44 2014 +0200
@@ -56,7 +56,8 @@
 	find contrib doc hgext i18n mercurial tests \
 		\( -name '*.py[cdo]' -o -name '*.so' \) -exec rm -f '{}' ';'
 	rm -f $(addprefix mercurial/,$(notdir $(wildcard mercurial/pure/[a-z]*.py)))
-	rm -f MANIFEST MANIFEST.in mercurial/__version__.py hgext/__index__.py tests/*.err
+	rm -f MANIFEST MANIFEST.in hgext/__index__.py tests/*.err
+	if test -d .hg; then rm -f mercurial/__version__.py; fi
 	rm -rf build mercurial/locale
 	$(MAKE) -C doc clean