merge revision(s) 44425,44460: [Backport #9320]

	* tool/make-snapshot: support new version scheme.

	* tool/make-snapshot: needs CXXFLAGS.  [ruby-core:59393][Bug #9320]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@45162 b2dd03c8-39d4-4d8f-98ff-823fe69b080e