More string stuff (was Nautilus Gtk stuff inventory)

[Joe Shaw <joe helixcode com>]

> -----------------
> nautilus-string.h
> -----------------
>     nautilus_strlen (returns 0 for NULL, following g_strdup's lead of
> allowing NULL)

Along these same lines, it seems that doing a g_strdup_printf("%s",
NULL) crashes on some machines (Solaris). Seeing as glib is supposed to
provide consistent results across architectures, this should probably be
changed to return "(null)" or possibly "". It goes along with g_strdup's
lead of allowing NULL.

Jacob seems to think that this is a severe enough problem that we might
want to backport it to 1.2, since most developers probably assume this
behavior and don't test on Solaris. It crashes on Solaris 2.7, but not on
Linux x86, apparently.

Joe