Configuration patches to handle threading and general tuning issues

[John David Anglin]

> libstdc++-v3 was completely rebuilt and reinstalled (with a little
> help to move gthr*.h files by hand) but only informal testing has
> commenced so far, no full bootstrap, no full regression test.
> However, I did check to ensure all the right macros are appearing
> where they should under this ../gcc/gthr*.h-based configuration style.

I did a complete bootstrap and check with unix/-pthread, unix/-fPIC
and unix/ under i686 linux.  I am down to two v3 FAILs for all modes.
The v3 FAILs are:

FAIL: 22_locale/codecvt_unicode_char.cc execution test
FAIL: 22_locale/codecvt_unicode_wchar_t.cc execution test

There are no g++ regressions either.  I am going to give it a whirl
under hpux.

Excellent work!
Dave
-- 
J. David Anglin                                  dave.anglin@nrc.ca
National Research Council of Canada              (613) 990-0752 (FAX: 952-6605)