def mkdir_if_necessary(dir, owner: nil, mode: nil)
      return if File.exist?(dir) || File.symlink?(dir)
      mkdir(dir, owner: owner, mode: mode)
      true
    end
def mkdir_if_necessary(dir, owner: nil, mode: nil)
      return if File.exist?(dir) || File.symlink?(dir)
      mkdir(dir, owner: owner, mode: mode)
      true
    end
Runs #mkdir, but ONLY if +dir+ doesn't already exist. Returns true if
 directory had to be created. This is useful with verbose?, to get an
 exact changelog.