While checking MKATF=no builds, i noticed that, in that case, we do
generate an almost useless `/usr/tests' tree.
While previously some shell tests could be run mannually, we can't now
because the interpreter switched to /usr/bin/atf-sh (since ATF 0.9).
Other test that require c/c++ APIs are not even built ... Only remains
a few input/results files.
Unless we plan to integrate stuff that will not use ATF, i'm currently
thinking of making tests set optional.
This will require a new mtree list (etc/mtree/NetBSD.dist.tests), a
new variable `test' in distrib/sets/sets.subr to allow generating the
corresponding `tests.tgz' archive. And maybe some other adjustements
somewhere ...
Before stepping into this one, what do people think ?