Log Message:
Update ruby-thor to 0.19.4.

* pkgsrc change: add pkg_alternatives support.

0.19.4, release 2016-11-28

* Rename Thor::Base#thor_reserved_word? to #is_thor_reserved_word?

0.19.3, release 2016-11-27

* Output a warning instead of raising an exception when a default option value
  doesn't match its specified type

0.19.2, release 2016-11-26

* Fix bug with handling of colors passed to ask (and methods like yes? and no?
  which it underpins)
* Allow numeric arguments to be negative
* Ensure that default option values are of the specified type (e.g. you can't
  specify "foo" as the default for a numeric option), but make symbols and
  strings interchangeable
* Add Thor::Shell::Basic#indent method for intending output
* Fix remove_command for an inherited command (see #451)
* Allow hash arguments to only have each key provided once (see #455)
* Allow commands to disable class options, for instance for "help" commands
  (see #363)
* Do not generate a negative option (--no-no-foo) for already negative boolean
  options (--no-foo)
* Improve compatibility of Thor::CoreExt::HashWithIndifferentAccess with Ruby
  standard library Hash
* Allow specifying a custom binding for template evaluation (e.g. #key? and
  #fetch)
* Fix support for subcommand-specific "help"s
* Use a string buffer when handling ERB for Ruby 2.3 compatibility
* Update dependencies