Remove unused _zip_rename define.

lib/zipint.h

diff --git a/lib/zipint.h b/lib/zipint.h
index edfc455..3be0ed6 100644
--- a/lib/zipint.h
+++ b/lib/zipint.h
@@ -63,13 +63,6 @@
 #define false   0
 #endif
 
-#ifdef HAVE_MOVEFILEEXA
-#include <windows.h>
-#define _zip_rename(s, t)	(!MoveFileExA((s), (t), MOVEFILE_COPY_ALLOWED|MOVEFILE_REPLACE_EXISTING))
-#else
-#define _zip_rename	rename
-#endif
-
 #ifdef _WIN32
 #if defined(HAVE__CLOSE)
 #define close		_close