Log Message:
Update shtk to 1.4:

Released on 2013-12-30.

* Added support for a user-defined SHTK_MODULESPATH variable.  This
  colon-separated, user-tunable variable lists the directories that
  contain modules.

* Added a modulesdir variable to shtk.pc so that third-party packages
  can install shtk-compliant modules into the shared directory.  This
  variable is also exposed by the SHTK_CHECK macro of shtk.m4 as
  SHTK_MODULESDIR.

* Added a new bool module with a shtk_bool_check function to convert a
  string to a boolean.

* Added a new cleanup module to simplify the installation and automatic
  execution of termination handlers.

* Fixed the config module in Mac OS X 10.9 to respect default values
  of configuration variables.