Log Message:
libxkbcommon: update to 0.8.0.

libxkbcommon 0.8.0 - 2017-12-15
==================

- Added xkb_keysym_to_{upper,lower} to perform case-conversion directly on
  keysyms. This is useful in some odd cases, but working with the Unicode
  representations should be preferred when possible.

- Added Unicode conversion rules for the signifblank and permille keysyms.

- Fixed a bug in the parsing of XKB key type definitions where the number
  of levels were determined by the number of level *names*. Keymaps which
  omit level names were hence miscompiled.

  This regressed in version 0.4.3. Keymaps from xkeyboard-config were not
  affected since they don't omit level names.

- New API:
  xkb_keysym_to_upper()
  xkb_keysym_to_lower()