Protect against error in user home directory computation
This is a quick fix. There are comments about other related issues and
better ways to do it.
2013-04-16 Didier Verna <didier@didierverna.net>
* src/util.lisp (home-directory): New warning condition.
(home-directory): Handle TRUENAME errors by returning NIL.
* src/synopsis.lisp (initialize-instance): Handle NIL user home
directory in the clon-search-path default value.
* src/options/path.lisp (convert): Mention the bug about
HOME-DIRECTORY returning NIL.
* TODO: Mention the bug about static computation of the default value
of the clon-search-path option.