configure.in: shvar_to_cpp in ruby

* configure.in: save configured load path values into verconf.in.
* common.mk (verconf.h): create from verconf.in with shvar_to_cpp.rb.
* tool/shvar_to_cpp.rb: turn shell variables into C macros.
  [Bug #7959]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40758 b2dd03c8-39d4-4d8f-98ff-823fe69b080e