Compat level needs to match the debhelper version in Debian.
Debian wheezy has 9, so there is no need to stay on ancient level 5.

made in 227510e0.
We now use lex->last_field->interval_list directly instead.

        Item_bool fixed to behave smarter with NOT operation.

MDEV-11039 - Add new scheduling algorithm for reducing tail latencies (for 10.2)

        strings/json_lib.c added as a JSON library.
        SQL frunction added with sql/item_jsonfunc.h/cc

Rebase

Sync upstream and rebase.

On PPC64 high-loaded server may crash due to assertion failure in InnoDB
rwlocks code.

This happened because load order between "recursive" and "writer_thread"
wasn't properly enforced.

Clean-up periodic mutex/rwlock waiters wake up. This was a hack needed to
workaround broken mutexes/rwlocks implementation. We must have sane
implementations now and don't need these anymore: release thread is
guaranteed to wake up waiters.

Removed redundant ifdef that has equivalent code in both branches.

Removed os0atomic.h and os0atomic.ic: not used anymore.

Clean-up unused cmake checks.