Consult ~condorauto/permitted-build-platforms to determine which platforms
to build.  This allows to easily and temporarily disable platforms.  Also,
append the contents of ~condorauto/append-to-builds to all submit files.  This
allows us to (among other things) temporarily enable Metronome-level debugging
on specific platforms.
Merge branch 'V8_2-branch' into V8_3_1-branch