10.6.8 and ffmpeg

[Ryan Schmidt]

> On Oct 30, 2016, at 3:13 AM, Davide Liessi <davide.liessi at gmail.com> wrote:
> 
> 2016-10-30 1:23 GMT+02:00 Ryan Schmidt <ryandesign at macports.org>:
>> If sdl2 can be built on Snow Leopard using a copy of the 10.7 SDK obtained from a later Xcode, and that sdl2 then works ok on Snow Leopard, then I'd be happy if we could come up with an official way to support that, and then we could do that on the buildbot, which would cover a lot of users' needs.
> 
> From libsdl's wiki (http://wiki.libsdl.org/Installation#Mac_OS_X):
> "SDL2 has dropped support for PowerPC Macs

Boo.

> and OS X versions older
> than 10.5 (SDL 1.2 still supports PPC and 10.0, though)."

Yay!

> Which implies that 10.5 is still supported, and indeed they describe
> the Mac binary download as "Intel 10.5+"
> (https://www.libsdl.org/download-2.0.php).

That's good.

> Libsdl2 not building on 10.6 is either a bug in MacPorts, a bug in
> libsdl2 or a bug in libsdl's documentation.

Not necessarily. They could have built the binary on 10.7, using the 10.7 SDK and the 10.5 deployment target. We currently don't attempt to do anything like that on the buildbot machines; instead, we always build on the version of macOS that will eventually run it.

mongodb is another port that could benefit from that. Their binary runs on 10.7, but doesn't build with the 10.7 SDK, but does build on 10.7 with the 10.8 SDK; see https://jira.mongodb.org/browse/SERVER-20320 . There it's less of a problem, because the latest Xcode for 10.7 includes the 10.8 SDK.

For 10.6 and earlier, where SIP is not an issue, and SDKs just go in /Developer/SDKs, maybe copying the 10.7 SDK into /Developer/SDKs is the simplest solution. I can do that on the buildbot machines, and we can write the libsdl2 portfile so that it uses that SDK if available and instructs the user how to download and install it if it's not yet there.