Add versions to platforms

[raimue@…]

Currently the platforms statement can only specify a platform like darwin, macosx, linux, freebsd and others, but cannot require a version of the platform. So this is a proposal to extend it to also include platform version numbers.

This would look like this:

platforms    darwin                  # as it is now
platforms    {darwin 7} {darwin 8}   # Darwin 7 or 8
platforms    {darwin >=8}            # Darwin 8 or higher
platforms    {macosx >=9.3}          # Mac OS X 10.5.3 or higher

If a platform does not match the requirements, the port should error out automatically when trying to install it. To enforce a specifc version, some ports are using pre-fetch {} blocks at the moment, these could be replaced with this new syntax.

[afb@…]

Replying to raimue@macports.org:

platforms {macosx >=9.3} # Mac OS X 10.5.3 or higher

Shouldn't that be {macosx >= 10.5.3} (or {darwin >= 9.3} perhaps) ?