def path_key
      # The ruby devkit needs ENV['Path'] set instead of ENV['PATH'] because
      # $WINDOWSRAGE, and if you don't set that your native gem compiles
      # will fail because the magic fixup it does to add the mingw compiler
      # stuff won't work.
      #
      # Turns out there is other build environments that only set ENV['PATH'] and if we
      # modify ENV['Path'] then it ignores that.  So, we scan ENV and returns the first
      # one that we find.
      #
      if windows?
        result = ENV.keys.grep(/\Apath\Z/i)
        case result.length
        when 0
          raise "The current omnibus environment has no PATH"
        when 1
          result.first
        else
          raise "The current omnibus environment has multiple PATH/Path variables."
        end
      else
        "PATH"
      end
    end
def path_key
      # The ruby devkit needs ENV['Path'] set instead of ENV['PATH'] because
      # $WINDOWSRAGE, and if you don't set that your native gem compiles
      # will fail because the magic fixup it does to add the mingw compiler
      # stuff won't work.
      #
      # Turns out there is other build environments that only set ENV['PATH'] and if we
      # modify ENV['Path'] then it ignores that.  So, we scan ENV and returns the first
      # one that we find.
      #
      if windows?
        result = ENV.keys.grep(/\Apath\Z/i)
        case result.length
        when 0
          raise "The current omnibus environment has no PATH"
        when 1
          result.first
        else
          raise "The current omnibus environment has multiple PATH/Path variables."
        end
      else
        "PATH"
      end
    end
The proper platform-specific "$PATH" key.

 @return [String]