ext/depend: fix dependency for nmake

* ext/depend (ENCOBJS, TRANSOBJS): use explicit path to ruby.h for
  nmake.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40187 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
object.c: extract common code

* object.c (id_for_setter): extract common code from const, class
  variable, instance variable setters.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40188 b2dd03c8-39d4-4d8f-98ff-823fe69b080e