contrib/showstack.py

automation: correct the path separator in LIBPATH on Windows

I haven't tried building the x86 installer, but happened to notice this when
working on the thg installer.  Experimenting in PowerShell seems to show that
LIBPATH was expanded at the end, but with ':' between, it effectively corrupted
`${root}\WinSDK\Lib` and the first path in LIBPATH.

Differential Revision: https://phab.mercurial-scm.org/D6642

# showstack.py - extension to dump a Python stack trace on signal
#
# binds to both SIGQUIT (Ctrl-\) and SIGINFO (Ctrl-T on BSDs)
r"""dump stack trace when receiving SIGQUIT (Ctrl-\) or SIGINFO (Ctrl-T on BSDs)
"""

from __future__ import absolute_import, print_function
import signal
import sys
import traceback

def sigshow(*args):
    sys.stderr.write("\n")
    traceback.print_stack(args[1], limit=10, file=sys.stderr)
    sys.stderr.write("----\n")

def sigexit(*args):
    sigshow(*args)
    print('alarm!')
    sys.exit(1)

def extsetup(ui):
    signal.signal(signal.SIGQUIT, sigshow)
    signal.signal(signal.SIGALRM, sigexit)
    try:
        signal.signal(signal.SIGINFO, sigshow)
    except AttributeError:
        pass