diff --git a/win32/Makefile.sub b/win32/Makefile.sub
index 6234bfb4b3..760f919b23 100644
--- a/win32/Makefile.sub
+++ b/win32/Makefile.sub
@@ -10,6 +10,7 @@ CHDIR = cd
 PATH_SEPARATOR = ;
 TZ =				# skip timezone tests
 PWD = $(MAKEDIR)
+empty =
 
 !ifndef MFLAGS
 MFLAGS=-l