Turn the numeric parameter to err_sfntbadglyph from wchar_t to

unsigned int, after a correspondent mentioned that DJGPP produces a
very scary warning about integer promotion making use of the former
in va_arg non-portable. Whether or not that's standards-justifiable,
it's certainly the case that we were casting _to_ wchar_t from
unsigned int in all cases of this error actually being used, so the
simplest thing is just to transfer the number through va_arg as
unsigned.

git-svn-id: svn://svn.tartarus.org/sgt/halibut@8112 cda61777-01e9-0310-a592-d414129be87e