constant.h: reduce rb_const_entry_t size on 64-bit

	* constant.h: reduce rb_const_entry_t size on 64-bit
	  Patch by Adam Avilla [ruby-core:60542] [Feature #9496]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44869 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2014-02-07

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44870 b2dd03c8-39d4-4d8f-98ff-823fe69b080e