* common.mk (MJIT_HEADER, MJIT_MIN_HEADER): added hook to separate
intermediate headers per archs.
* defs/gmake.mk: build mjit headers per -arch options, and then
merge the headers with `#ifdef`s.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62245 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
nobu