The compiler is irrelevant here as stdint.h can come from a variety of sources. There's no reason to not have stdint.h, even on ancient as dirt embedded systems stuck on C89. Even in the worst case of there's no vendor-provided one you can still just define it yourself using a copy from almost anywhere else, there's very little to it.
stdint.h can't be reliably be premade. A compiler is completely free to, say, define sizeof(unsigned int) to anything as long as it can represent at least 65535. stdint.h has to work with the C base types, so it does have to be customized for a particular compiler.
