daefb1b012
Summary: Freestanding builds have `stddef.h` and `stdint.h` but not `stdlib.h`. We don't actually use any `stdlib.h` definitions in the OpenMP headers, and some definitions from this header are usable without the OpenMP runtime (allocators) so we should be able to do this. This ignores the include if possible, removing the implicit include would possibly break some applications so it stays here.