[Cryptech Tech] C standard

[Rob Austein]

Question I only just realized I should have asked a while ago: what's
our target standard for C code?  ANSI?  C99?  C11?

I ask because my own default, from years (OK, decades) of habit, is
ANSI C.  C99 has features that I wouldn't mind being able to use, the
question is whether we're comfortable with requiring compiler support.

GCC and Clang both support C99.  Not sure about Microsoft, doubt we
care about Microsoft for the green layer, but maybe we do for yellow.

Note that we are already requiring stdint.h, which, strictly speaking,
is a C99 thing.  Of course, adding a trivial header file is not the
same supporting new language semantics.

If nobody objects, I'll assume that C99 is OK and start using it.