Require more recent glibc on F27
On CPUs with AVX-512 instruction set, ntpd sometimes segfaults because
PTHREAD_STACK_MIN is too small. The bug has been fixed in
glibc-2.26-24.fc27.x86_64 or later.
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1564527
Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Alexey Slaykovsky <alexey@slaykovsky.com>
Reviewed-By: Alexey Slaykovsky <alexey@slaykovsky.com>