Comment 16 for bug 156575

So, after talking to Celso it seems that it should be turned on on a
per-archive basis. The hardest bit of that is deciding what to call the
flag. build_debug_symbols? That's what I've used for now. All three
modified components are backwards compatible.

Problems:
 - DDEB publishing is currently disabled. Should that be
   unconditionally reenabled, or should there be a separate Archive
   flag to further restrict archive disk bloat?
 - Primary builds will fail to upload after these changes, until a
   DEBUG archive is created.
 - Older series need the pkg-create-dbgsym patch as well. How is that
   done?