to tech-pkg:
=====
* USE_BUILDLINK3=YES will be unconditional. (In fact, USE_BUILDLINK3 will
be ignored altogether by mk/; but see below.)
* NO_BUILDLINK and NO_WRAPPER will be ignored by mk/. If a build happens,
these phases will happen.
* The existing NO_BUILD will imply the previous NO_BUILDLINK and NO_WRAPPER.
If no build happens, those phases are not needed.
* NO_TOOLS will be ignored by mk/. The tools phase, which provides much
more than just the C compiler, will always happen regardless of package.
This will make metapackage builds only slightly slower, in trade for far
less user error.
