"None"; this should be equivalent to sys.exit(0).

with an instance of a derived class B would really raise an A, not a
B.  Since Barry fixed this anomalous behaviour, I though I might as
well fix the test!  (Hmm, Barry, did you not run the tests or did you
miss that test_opcodes failed?)

(1) Use PyErr_NewException("module.class", NULL, NULL) to create the
    exception object.

(2) Remove all calls to Py_FatalError(); instead, return or
    ignore the errors -- the import code now checks PyErr_Occurred()
    after calling a module's init function, so it's no longer a
    fatal error for the initialization to fail.

Also did some small cleanups, e.g. removed unnecessary test for
"already initialized" from initfpectl(), and unified
initposix()/initnt().

I haven't checked this very thoroughly, so while the changes are
pretty trivial -- beware of untested code!

plat-win, get rid of test (which is now a package).

tstate swapping.  Only the acquiring and releasing of the lock is
conditional (twice, under ``#ifdef WITH_THREAD'' and inside ``if
(interpreter_lock)'').

was a single '-'.  Thanks to Andrew Kuchling.

causes ugly noises under Windows.

instance's class is a subclass of this, then use the instance's class
as the exception type.

again (Mark Hammond is the cause of all this).

Use "re" module, making it threadsafe.

first.  Don't store the traceback as a local variable, to avoid
circular references.

os.fdopen() calls unbuffered.  I presume that it's enough if we can
make all three of them (for stdin, stdout, and stderr) unbuffered and
don't need to specify different buffer sizes per file -- that would
complicate the interface more than I care for.

This one works!  However it requires using a modified version of
tclNotify.c (provided), which requires access to the Tcl source
to compile it.  In order to enable this hack, add the following
to the Setup line for _tkinter:
   tclNotify.c -DHAVE_PYTCL_WAITUNTILEVENT -I$(TCL)/generic
where TCL points to the source tree of Tcl 8.0.  Other versions
of Tcl are not supported.

The tclNotify.c file is copyrighted by Sun Microsystems; the
licensing terms are in the file license.terms.  According to this
file, no further permission to distribute this is required,
provided the file license.terms is included.  Hence, I am checking
that in, too.

instead it is added to MACHDEPPATH in Modules/Setup.in

maps errno numbers to errno names (e.g. EINTR), and errorcode maps
them to message strings.  (The latter is redundant because
the new call posix.strerror() now does the same, but alla...)

Apparently the traceback object doesn't contains the right linenumber
when -O is used.  Rather than guessing whether -O is on or off, use
tb_lineno() unconditionally.