New upstream snapshot from 20180127:

* New upstream snapshot from 20180127:
  - Fix stack corruption by __pthread_register_cancel.  Closes: #887078,
    #887886.
  - debian/patches/hurd-i386/local-hurdsig-global-dispositions-version.diff:
    rebased.
  - debian/patches/hurd-i386/git-exec_filename.diff: upstreamed.
  - debian/patches/hurd-i386/tg-faccessat.diff: upstreamed.
  - debian/patches/hurd-i386/local-exec_filename.diff: upstreamed.