SDL: update to 1.2.68

[ii8]

This upgrade switches the legacy SDL to sdl12-compat as recommended by the SDL developers.
Pros are: It's maintained and gets fixes, sdl 1.2 applications work on wayland with this, it's simpler and requires less disk space. As far as I can tell there are no downsides.

Testing the changes

• I tested the changes in this PR: YES

Local build testing

• I built this PR locally for my native architecture, x86_64 musl
• I built this PR locally for these architectures (if supported. mark crossbuilds):
  • armv6l
  • armv6l-musl

[classabbyamp]

What do other distros do with SDL1 vs SDL12-compat? maybe it would be better to create sdl12-compat as a separate package and transition all sdl1 packages to it?

[ii8]

Alpine and Arch have only sdl12-compat, no SDL package.

It might cause people problems if packages were gradually transitioned because it's tricky to have both SDL1 and sdl12-compat installed at the same time, they have the same files in the same places.

Could maybe add sdl12-compat as a separate package that has a replaces="SDL>=0" in it, but I don't know how that works exactly with transitioning packages that depend on sdl.

In the end the only difference is the name.