* gc.c: remove unused macros.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46999 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2014-07-30

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47000 b2dd03c8-39d4-4d8f-98ff-823fe69b080e