RFC: Drop PPC support

[Takeshi Enomoto]

> Historically we officially support the current and previous Mac OS X release (while not doing anything to on-purpose break older releases / being willing to accept patches to make things work on older releases).

If we are not going to change this policy,
PPC is no longer supported.
It is up to the maintainers or the port.
We don't have to remove what are still available for PPC.

Personally I still use a big-endian Power Mac and try to maintain some ports
as far as I can.

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Takeshi Enomoto
takeshi at macports.org