[Xastir-Dev] configure checking for motif

[RZG]

I just did a silly test on an old system of mine that doesn't have
motif/lesstif installed. Configure reported "(none)" for motif and
headers, but just went on as though nothing happened. Since we're
finding people missing the devel files (and in my silly case the library
itself), shouldn't the configure script bail out and tell the user
to install it?

--Reuven (KB3EHW)