* introduce the mbstate_t typedef.
impacts gnu libiconv, which has already been taken care of.
* Prepare for mb stuff to really exist, replace macro MB_CUR_MAX with
an external variable __mb_cur_max (impacts libX11 and various ports).
* use mbstate in all the mb <-> wchar functions with state.
* add a stub iswctype function allowing some ports to compile.
bash and gdiff are missing wcscoll, and need to be told there's no i18n
until this is fixed.
Discussed and matthieu, otto, millert, kettenis, deraadt.
Major libc bump