make-snapshot: don't store symlinks by 7z for reproduceable pacakges

tool/make-snapshot

@@ -54,7 +54,7 @@ PACKAGES = {
 DEFAULT_PACKAGES = PACKAGES.keys - ["tar"]
 if !$no7z and system("7z", out: IO::NULL)
   PACKAGES["gzip"] = %w".tar.gz 7z a dummy -tgzip -mx -so"
-  PACKAGES["zip"]  = %w".zip    7z a -tzip  -mx -mtc=off" << {out: IO::NULL}
+  PACKAGES["zip"]  = %w".zip    7z a -tzip -l -mx -mtc=off" << {out: IO::NULL}
 elsif gzip = ENV.delete("GZIP")
   PACKAGES["gzip"].concat(gzip.shellsplit)
 end