SDL2: compatibility fixes for macOS < 10.15

[jmroot]

Description

Several recent changes inadvertently broke SDL2 on various macOS versions older than 10.15. These changes restore compatibility.

With the kAudioChannelLayoutTag_* enum values, when on an OS version that doesn't support the correct layout, I'm not sure if it's better to error out as I'm currently doing, or to use a not quite right channel layout as in previous versions.

[slouken]

In general this looks good. Once CI passes and you've done testing on new and old versions of macOS and iOS, can you create a PR for SDL3 as well?

[jmroot]

In general this looks good. Once CI passes and you've done testing on new and old versions of macOS and iOS, can you create a PR for SDL3 as well?

Oh, I assumed SDL3 wouldn't be supporting macOS versions this old. Happy to make the PR if that's not the case.

There seems to be an issue with the NSInvocation stuff, can you by any chance spot my mistake?

[jmroot]

OK, I think I got it.

[slouken]

We're probably going to bump the minimum deployment target for macOS to 10.15 in SDL3, so anything here relevant for that version would be great.

[slouken]

What versions of iOS and macOS have you tested building and running this code?

[jmroot]

I'm unable to test on iOS. Lightly tested running on macOS 14.7.2, 10.8.5 and 10.7.5 so far. Successful builds on all major macOS versions from 10.7 through to 14.

[jmroot]

We're probably going to bump the minimum deployment target for macOS to 10.15 in SDL3, so anything here relevant for that version would be great.

This is all only needed for <= 10.14.

[slouken]

Merged, thanks!