(LTH-172) Add support for RHEL-9(glibc 2.34)

Adapted from catchorg/Catch2@f83d032

On GLIBC >= 2.33, `MINSIGSTKSZ` is not a constant. This can be detected
at compile time by the presence of either `_SC_SIGSTKSZ_SOURCE` or
`_GNU_SOURCE`.

If either are define, hardcode the size we want rather than compare it,
since we can't do that in a constant expression anymore.