win32/rm.bat: remove each files

* win32/rm.bat: removing by wildcard errs on network file system, so
  remove each files.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38782 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
setup.mak: -osname-

* win32/setup.mak (-osname-): separate from -runtime- and just
  compile.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38783 b2dd03c8-39d4-4d8f-98ff-823fe69b080e