The `raison d'etre' for this interface is that the working directory
is sometimes inaccessible, and getcwd is not robust or as efficient.
So, we prefer to use the open/fchdir approach, but fall back on
- getcwd if necessary.
+ getcwd if necessary. This module works for most cases with just
+ the getcwd-lgpl module, but to be truly robust, use the getcwd module.
Some systems lack fchdir altogether: e.g., OS/2, pre-2001 Cygwin,
SCO Xenix. Also, SunOS 4 and Irix 5.3 provide the function, yet it