Package builds are performed in a jail populated by the portbuild script using the ${arch}/${branch}/builds/${buildid}/bindist.tar file.
The makeworld command builds a world from the ${arch}/${branch}/builds/${buildid}/src/ tree and installs it into ${arch}/${branch}/builds/${buildid}/bindist.tar. The tree will be updated first unless -novcs is specified. It should be run as root:
# /var/portbuild/scripts/makeworld ${arch} ${branch} ${buildid} [-novcs]
The bindist.tar tarball is created from the previously installed world by the mkbindist script. It should be also be run as root:
# /var/portbuild/scripts/mkbindist ${arch} ${branch} ${buildid}
The per-machine tarballs are located in ${arch}/clients.
The bindist.tar file is extracted onto each client at client boot time, and at the start of each pass of the dopackages script.
For both commands above, if ${buildid} is latest, it may be omitted.