Ruby

• win32/setup.mak: use findstr.exe instead of find.exe, because all
  target build platforms should have findstr.exe, and, find.exe often
  means another command such as cygwin's.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@29767 b2dd03c8-39d4-4d8f-98ff-823fe69b080e