This header is more or less the same across libc implementations.
`musl` uses its `_Noreturn` macro to detect which `noreturn`
should be used: C11 or GCC's extension as a fallback.
`glibc` simply defines `noreturn` as `_Noreturn`.
This implementation is based off of `musl`'s.
`_Noreturn` is deprecated as of C23.
Josh Megnauth