Title: #5357: Provide missing defines which otherwise are available on glibc system…
Well, it seems this is [widespread
to fix this issue while
building against Musl. I wonder why it can't be included in Musl instead...
Nonetheless, taking into account `util/util.h` includes `sys/stat.h`, I think this patch
is not dangerous. But I will let others to provide an opinion as well.
(Perhaps it makes sense to add a source code comment with a note why we might need to
define this (build against musl))
See the full comment at https://github.com/SSSD/sssd/pull/5357#issuecomment-706045059