intern.h: macro rb_check_arity
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39610 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
intern.h: macro rb_check_arity
compatibility checking by ifdef.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39610 b2dd03c8-39d4-4d8f-98ff-823fe69b080e