[compiler-rt] [compiler-rt] Define `__STDC_FORMAT_MACROS` to ensure `PRId64` is available (PR #102980)

[Florian Mayer via llvm-commits]

fmayer wrote:

Thanks for the PR.

Looks good to me, but adding someone from scudo to take a look.

https://github.com/llvm/llvm-project/pull/102980