[cff, truetype] Integer overflows.

Reported as

  https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=2216
  https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=2218

* src/cff/cf2fixed.h (cf2_fixedAbs): Use NEG_INT32.

* src/truetype/ttinterp.c (Ins_IP): Use SUB_LONG.
3 files changed