.gdbinit: revert colored prompt

* .gdbinit: revert colored prompt because incremental search does not
  work well with invisible sequence in prompt.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39288 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
configure.in: unexpand_shvar

* configure.in (unexpand_shvar): regularize a shell variable by
  unexpanding shell variables in it.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39289 b2dd03c8-39d4-4d8f-98ff-823fe69b080e