* tool/mkconfig.rb: reconstruct comma separated list values. a
command line to Windows batch file is splitted not only by spaces
and equals sign but also by commas and semicolons.
command line to Windows batch file is split not only by spaces
and equal signs but also by commas and semicolons.
merge revision(s) 39507,39508: [Backport #7963]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@39909 b2dd03c8-39d4-4d8f-98ff-823fe69b080e