supported_platforms platform_0 (like noarch)

[Bradley Giesbrecht]

We could fetch platform indifferent ports from packages.macports.org from _ANY_ OS.

name                             foo
version                          1.2.3
supported_archs         noarch
supported_platforms	platform_0

Example package archive:
foo-1.2.3_0.platform_0.noarch.tbz2


Regards,
Bradley Giesbrecht (pixilla)