thread-safe exceptions (first cut)

[Teemu Torma]

    From:  scott snyder <snyder@d0sgif.fnal.gov>
    Date:  Fri, 12 Sep 1997 01:35:01 -0500 (CDT)

    Here's a first cut at thread-safe exceptions for egcs.
    This seems to work for me on Digital Unix, but it almost certainly
    needs more work before it can be added to the tree.  However, i'm not
    going to be able to do any more on this for the next several weeks
    (i'll be out of the country), so i thought i should send this around
    in case someone else wanted to work on it.
    
It seems to work just fine also on Solaris 2.5.1 (UltraSparc).

Teemu