This version of slang includes patches for multibyte character support,
and line-drawing characters on unicode consoles.

These patches change the API/ABI of slang slightly.

Notable changes:

- SLSMG_HLINE_CHAR (and friends) are no longer constants, so they
  can not be used in static initializers.
- SLsmg_init_smg() now calls setlocale(). If you do not wish this
  to happen, set SLsmg_Setlocale to 0. Note: doing so may hinder
  the ability of your application to use line-drawing characters.