libX11: update to 1.7.0.

libX11 version 1.7.0 includes a new API, hence the change from the 1.6
series to 1.7:

* XSetIOErrorExitHandler which provides a mechanism for applications
  to recover from I/O error conditions instead of being forced to
  exit. Thanks to Carlos Garnacho for this.

This release includes a bunch of bug fixes, some which have been pending for over three years:

* A bunch of nls cleanups to remove obsolete entries and clean up
  formatting of the ist. Thanks to Benno Schulenberg for these.

* Warning fixes and other cleanups across a huge swath of the
  library. Thanks to Alan Coopersmith for these.

* Memory allocation bugs, including leaks and use after free in the
  locale code. Thanks to Krzesimir Nowak, Jacek Caban and Vittorio
  Zecca for these.

* Thread safety fixes in the locale code. Thanks to Jacek Caban for
  these.

* poll_for_response race condition fix. Thanks to Frediano Ziglio for
  the bulk of this effort, and to Peter Hutterer for careful review
  and improvements.

Version 1.7.0 includes a couple of new locales:

* ia and ie locales. Thanks to Carmina16 for these.

There are also numerous compose entries added, including:

* |^ or ^| for ↑, |v or v| for ↓, ~~ for ≈. Thanks to Antti
    Savolainen for this.

* Allowing use of 'v' for caron, in addition to 'c', so things like
  vC for Č, vc for č. Thanks to Benno Schulenberg for this.

* Compose sequences LT, lt for '<', and GT, gt for '>' for keyboards
  where those are difficult to access. Thanks to Jonathan Belsewir
  for this.

(wiz)