updated for version 7.0116
diff --git a/src/Make_mvc.mak b/src/Make_mvc.mak
index e4b3446..164ed50 100644
--- a/src/Make_mvc.mak
+++ b/src/Make_mvc.mak
@@ -734,7 +734,8 @@
 	- if exist tags del tags
 
 clean:
-	- $(DEL_TREE) $(OUTDIR) auto
+	- if exist $(OUTDIR)/nul $(DEL_TREE) $(OUTDIR)
+	- if exist auto/nul $(DEL_TREE) auto
 	- if exist *.obj del *.obj
 	- if exist $(VIM).exe del $(VIM).exe
 	- if exist $(VIM).ilk del $(VIM).ilk