* 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.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@39909 b2dd03c8-39d4-4d8f-98ff-823fe69b080e