Re: xassert in dispextern.h

[Miles Bader]

The right answer is to change those xasserts (and _only_ those) which
cause a problem or test something silly or are insanely inefficient
[99% are quite efficient] to use some other macro, like "gdassert" or
something, and make gdassert dependent on GLYPH_DEBUG.

[I should note that the thing which caused me to originally enable
xassert by default is that it caught (I always have it enabled) a case
where iterator stacks could overflow -- something that otherwise would
just result in rare, hard to debug, memory corruption.]

-Miles