using new `@comment DEPORIGIN:...' directive. This would allow us to make
many neat things including:
- easier binary upgrades;
- source upgrades without using external tools by simply extending
bsd.port.mk and pkg_install tools;
- mixed-mode upgrades (source + binary);
- depreciate and deorbit silly +REQUIRED_BY files in the near future.
This feature is no-op until appropriate bsd.port.mk patch is committed, and
even when it is already committed packages generated will remain 100%
compatible with old set of pkg_install tools (module all those neat
features, of course).
MFC after: 6 days
842eb4b30a