make-snapshot: extract gems

* tool/make-snapshot (package): extract bundled gems for package.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49291 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

tool/make-snapshot

@@ -301,6 +301,7 @@ def package(vcs, rev, destdir, tmp = nil)
       IO.popen(cmd, "w") do |f|
         f.puts mk
         f.puts "after-update::", "clean-cache $(CLEAN_CACHE): after-update", "prereq: clean-cache $(CLEAN_CACHE)"
+        f.puts "extract-gems:", "after-update:: extract-gems"
       end
       clean.push("rbconfig.rb", ".rbconfig.time", "enc.mk")
       print "prerequisites"