Show build logs on console by default, to make build cluster fallouts
investigation easier.

 Add option (default OFF) for old behavior if somebody needs it.

 Bo functional changes, package results are bit-equivalent, so no
PORTREVISION bumps.


git-svn-id: svn+ssh://svn.freebsd.org/ports/head@373566 35697150-7ecd-e111-bb59-0022644237b5