Port trees for specific versions of MacOS

[Ken Cunningham]

In <https://trac.macports.org/ticket/50448#comment:17> Rene mentions the idea of generating port tree overlays for specific versions of MacOS, to preserve compatible versions of ports which have moved beyond the capabilities of that OS.

I'd just like to mention that I've been working on this on my own for a while now, and have such trees in place, and available for contributions.  Anyone interested, feel free to suggest or contribute, please.

It was always my hope this might someday become part of MacPorts, or at least suggested for users.

Best,

Ken

Tiger:
<https://github.com/kencu/TigerPorts>

Leopard:
<https://github.com/kencu/LeopardPorts>

SnowLeopard:
<https://github.com/kencu/SnowLeopardPorts>

Lion:
<https://github.com/kencu/LionPorts>