wrapper around the system call with the same name.  Also added
test cases, doc changes and NEWS entry. Thanks Jason and Ralf
Schmitt.

This adds signal.set_wakeup_fd(fd) which sets a file descriptor to
which a zero byte will be written whenever a C exception handler runs.

I added a simple C API as well, PySignal_SetWakeupFd(fd).

protected by "if verbose:", which caused the test to fail on
all non-Windows boxes.

Note that I deliberately didn't convert this to unittest yet,
because I expect it would be even harder to debug this on Tru64
after conversion.

appears to be utterly insane.  Plug some theoretical
insecurities in the test script:

- Verify that the SIGALRM handler was actually installed.

- Don't call alarm() before the handler is installed.

- Move everything that can fail inside the try/finally,
  so the test cleans up after itself more often.

- Try sending all the expected signals in
  force_test_exit(), not just SIGALRM.  Since that was
  fixed to actually send SIGALRM (instead of invisibly
  dying with an AttributeError), we've seen that sending
  SIGALRM alone does not stop this from hanging.

- Move the "kill the child" business into the finally
  clause, so the child doesn't survive test failure
  to send SIGALRM to other tests later (there are also
  baffling SIGALRM-related failures in test_socket).

- Cancel the alarm in the finally clause -- if the
  test dies early, we again don't want SIGALRM showing
  up to confuse a later test.

Alas, this still relies on timing luck wrt the spawned
script that sends the test signals, but it's hard to see
how waiting for seconds can so often be so unlucky.

test_threadedsignals:  curiously, this test never fails
on Tru64, but doesn't normally signal SIGALRM.  Anyway,
fixed an obvious (but probably inconsequential) logic
error.

at stopping test_signal from hanging forever on the Tru64
buildbot.  That could be because there's no such thing as
signal.SIGALARM.  Changed to the idiotic (but standard)
signal.SIGALRM instead, and added some more debug output.

and may need to be reverted if it causes problems.

[ 971323 ] make test_signal less annoying
after some comments on IRC from a highly opinionated australian who
wishes to remain anonymous.

I'm not going to have the time or energy to get this working x-platform
-- anyone who does is welcome to the code!

imports e.g. test_support must do so using an absolute package name
such as "import test.test_support" or "from test import test_support".

This also updates the README in Lib/test, and gets rid of the
duplicate data dirctory in Lib/test/data (replaced by
Lib/email/test/data).

Now Tim and Jack can have at it. :)

[ 559250 ] more POSIX signal stuff

Adds support (and docs and tests and autoconfery) for posix signal
mask handling -- sigpending, sigprocmask and sigsuspend.

'verify' iff it's used by a test module...

and replaces them with a new API verify(). As a result the regression
suite will also perform its tests in optimization mode.

Written by Marc-Andre Lemburg. Copyright assigned to Guido van Rossum.

to signify a test that should be marked as 'skipped' rather than 'failed'.
Also 'document' it, in README.

test_*: converted to the new test harness.  GvR note!  test_signal.py
works interatively (i.e. when verbose=1) but does not work inside the
test harness.  It must be a timing issue, but I haven't figured it out
yet.