ck_spinlock: Add ck_spinlock_anderson_locked.
ck_pr: Add ck_pr_fence_strict_atomic for x86-64.
ck_spinlock: Add ck_spinlock_ticket_locked.
ck_spinlock: Add ck_spinlock_clh_locked.
regressions: Add ck_spinlock locked coverage.
ck_spinlock: Acquire semantics for old locked operations.

Even though the intended use-case is for testing, developers
may want correctness guarantees in other situations.
ck_spinlock: Weaken volatile store in clh_lock.
ck_elide: General lock elision framework.

This allows users to wrap any single-argument lock implementation
to support lock elision. Built-in lock types will make use of this
facility.
ck_rwlock: Migrate to ck_elide.h.
ck_spinlock: Migrate to ck_elide.h.

Pending unit test updates.