devel/lace14: update to 1.5.1

This fixes the build on armv7 and i386.
Several patch files have been upstreamed.
A likely race condition still remains, causing one of the unit tests
to fail, but it seems to be hard to trigger in practice. Will continue
to evaluate this issue with upstream.

Changelog: https://github.com/trolando/lace/blob/lace-1/CHANGELOG.md

Approved by: yuri
See also: https://github.com/trolando/lace/issues/16
Differential Revision: https://reviews.freebsd.org/D51737