* tool/generic_erb.rb, tool/id2token.rb: add --path-separator option
for mingw where make and built ruby live in different world.
* tool/vpath.rb: extract from tool/instruction.rb.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37985 b2dd03c8-39d4-4d8f-98ff-823fe69b080e