pack: Simplify signed integer packing calculation

Because of the fact that uintmax_t guarantees at least a full 64 bit
width and because of C's behavior when a signed type is converted to an
unsigned type and the value is out of range, the new code just
sign-extends and converts to a uintmax_t wide two's complement signed
value.

As an aside, the old code was written forgetting the fact that that
uintmax_t + intmax_t would be first converted to uintmax_t + uintmax_t
before being evaluated. The end result was the same except it ended up
being offset by 2^8s.

0 files changed, 0 insertions, 0 deletions