There's nothing wrong with sticking to C89, but honestly, stdint.h is hard to pass up. That said, you can define your own sized integers using the stdint names

There's nothing wrong with sticking to C89, but honestly, stdint.h is hard to pass up. That said, you can define your own sized integers using the stdint names in about a few dozen lines, since you don't really want to be using most of the stuff in the standard version.