g_strchug/g_strchomp/g_strstrip crash

[Joe Shaw <joe helixcode com>]

If a string passed to the g_strchug/g_strchomp/g_strstrip functions
consists of all spaces, it crashes. In these cases, I think it's probably
appropriate to return a g_strdup(""), but I wanted to run by the list to
see if everyone agrees as opposed to returning a NULL before I whip up a
patch.

Opinions?

Joe