cmake: detect and use sigdescr_np() if available

cmake: detect and use sigdescr_np() if available

sys_siglist is deprecated with glibc 2.32. A new thread-safe and
async-signal safe sigdescr_np() function is provided, so use it if
available.

Fixes: https://tracker.ceph.com/issues/47187
Signed-off-by: David Disseldorp <ddiss@suse.de>
(cherry picked from commit b9b6faf66ae67648626470cb4fc3f0850ac4d842)

Conflicts:
        CMakeLists.txt
	cmake/modules/CephChecks.cmake
- CephChecks.cmake file does not exist in nautilus; manually cherry-picked the
  change in that file to top-level CMakeLists.txt