git: 7fa2f2a62f04 - main - Rename NO_WERROR -> MK_WERROR=no

[Mark Millard]

The following error message makes no mention of WITHOUT_WERROR= use and stops the
build. As far as I can tell normally one does not use MK_WERROR= directly.

make: "/usr/fbsd/mm-src/share/mk/bsd.opts.mk" line 110: "NO_WERROR is defined, but deprecated. Please use MK_WERROR=no instead."

Also: How about an UPDATING entry about the incompatible build
environment requirements, given the lack of allowing the old
notation for a time?

===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)