save and restore the tstate, but explicitly calling
PyEval_SaveThread() does reset it! While I think about how to fix
this for real, here's a fix that avoids getting a fatal error.
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.
while one thread is blocked in mainloop(). Also, handle signals (not
just interrupts) as soon as they happen.
Cleanup: remove support for Tcl/Tk versions 7.4/4.0. (I've confirmed
that it works for 7.5/4.1 and 7.6/4.2, as well as 8.0b2.)
Coding style change: instead of ``func (args)'', write ``func(args)''
everywhere.
Minor functionality change: use PyArg_ParseTuple everywhere. This
should only affect the errors reported for bad argument lists; in
particular, deletefilehandler() is much clearer about what's going
on.
(XXX Still to do: Mac and Win ports to 8.0b2.)