Fix long file name bug reported on SCO Open Desktop 2.0 by Ulf Lunde

Fix long file name bug reported on SCO Open Desktop 2.0 by Ulf Lunde
<Ulf.Lunde@kvatro.no> and Dag H. Wanvik <Dag.H.Wanvik@kvatro.no>.

* coffread.c (getfilename):  Eliminate COFF_NO_LONG_FILE_NAMES
test, which is apparently left over from when we used native
include files and couldn't depend on the member names being there.
* tm-3b1.h, tm-altos.h, tm-i386v.h:  Don't set it.

ALso fix this in tm-i860.h which isn't ChangeLogged since it's sanitized out
for lack of paperwork.