[RFA] libiberty warning fixes for OSX

[DJ Delorie]

> Should the declaration be deleted?  I believe that everything now uses 
> lbasename() (well at least it did a few months ago).

I hesitate to do so, as it would create a backwards compatibility
issue.  Even if nothing *we* know of should use it (in which case, the
declaration is harmless), there may be other packages that we don't
know about that require it.

Perhaps, though, we need better protection for it.  I wish there were
a way for libiberty's configure to configure the include directory
headers also.  Sigh.