Upgrade to SDL3

[midwan]

Now that SDL3 is released, it should be tested to see how well things work with it.
The migration guide is here: https://github.com/libsdl-org/SDL/blob/main/docs/README-migration.md

SDL3 releases: https://github.com/libsdl-org/SDL/releases

This should be done in a separate, test branch. I suspect it will take quite a while before everything is migrated properly and we will need time for testing things.

Check if all supported platforms have SDL3 available.

[giantclambake]

Man, that's quite the API change ~ having moved this box to debian testing (trixie), I see libsdl3-0 (-dev) are available targets, so that probably infers adoption in debian next at a guess...

...just ftr, there's enough different between bookworm and trixie, that I use a different box for testing amiberry against debian bookworm, so once you spin-up a separate branch, it's easy enough for me to test things ;)

Current state of play ... https://packages.debian.org/search?searchon=sourcenames&keywords=libsdl3

HTH

[agreppin]

I tested a build with sdl2-compat and got an assert in a mutex. Seems a work in progress worth to be checked again later.

[midwan]

Well, this issue is about moving the code to use SDL3 directly, not through a compatibility layer. It's a long-term project, since it will take a while to do so, and we'll probably have to keep SDL2 around for a while longer as well (at least until SDL3 is available everywhere, not sure if it's in the older distros).

[ut316ab]

I tested a build with sdl2-compat and got an assert in a mutex. Seems a work in progress worth to be checked again later.

What version of sdl2-compat? If it's the same issue I ran into it was fixed in the newest versions of sdl2-compat and SDL3 see libsdl-org/sdl2-compat#264

However, this does go to show, that taking some time before adopting SDL3 might be beneficial.

[agreppin]

@ut316ab sdl2-compat commit 922171f