Merge pull request #400 from kw-andy/fix-makefile

Fix Makefile

Author: christopheNan

Makefile

@@ -36,7 +36,7 @@ endif
 
 $(SPHINX_CONF):
 	git clone --depth 1 --branch $(BRANCH) https://github.com/python/cpython.git $(CPYTHON_CLONE)
-	[ -n "$(COMMIT)" ] && i=1; while ! $$(git -C $(CPYTHON_CLONE) checkout $(COMMIT)); do i=$$((i * 2)); git -C $(CPYTHON_CLONE) fetch --depth $$i; done
+	[ -n "$(COMMIT)" ] && (i=1; while ! $$(git -C $(CPYTHON_CLONE) checkout $(COMMIT)); do i=$$((i * 2)); git -C $(CPYTHON_CLONE) fetch --depth $$i; done) || true
 
 
 .PHONY: upgrade_venv