bug#18726: dirname & basename

[Alan Stebbens]

If dirname is given an argument of "-ANYTHING", it should return the empty
string.

If basename is given an argument of "-ANYTHING", it should return
"-ANYTHING".

Both of these functions check *syntax*; they do not test the existence of
the argument.

The "-" character is a legitimate filename character, and the path "-FOO"
is a filename path component (even if unwise).

Currently, both programs return an error about '-X' where 'X' is an invalid
option.

This error occurred in a script using "$0", eg: dirname $0, and the script
was started with 'bash', and '$0' was '-bash'.

-- 
Alan K. Stebbens
Software Architect
Ecorithm, Inc.
805-886-8886