we need to set TARGET and TARGET_ARCH to get a correct WMAKEENV.
I am setting both to i386 since this is what picobsd is used for,
though there might be a better fix.
Add initial support for parallel make. This is disabled right now,
because there are incorrect dependencies somewhere which require
to run picobsd 2-3 times to complete a build.
MFC after: 2 weeks
7f2428704d