Include compiler name in archive name

[Ryan Schmidt]

There have been plenty of problems reported by Lion users who have upgraded to Xcode 4.3+ and have subsequently encountered build errors because the compiler locations changed, yet the old compiler locations were included in the files some ports installed -- python, qt4-mac, perl, apr -- https://trac.macports.org/wiki/ProblemHotlist#xcode-select

To a lesser extent we had the same problem when Lion or Snow Leopard users upgraded to Xcode 4.2.

We also had great troubles when users upgraded from Leopard to Snow Leopard, or Snow Leopard to Lion, without upgrading all ports -- https://trac.macports.org/wiki/Migration -- which we somewhat fixed by making the OS version part of the archive name, and part of what MacPorts checks when checking if ports are outdated.

Might we now also consider similarly adding the compiler name to the archive name and the outdated checks?