* benchmark/gc/gcbench.rb: add some options to make quiet.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43543 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* gc.c (Init_GC): add GC::OPTS to show options.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43544 b2dd03c8-39d4-4d8f-98ff-823fe69b080e