SDL_mixer2: add universal option

Matches the other SDL2 libraries.

Closes #29741.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
sbt 0.13.5

Closes #29732.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
sbt: quotes
Prefer Dir.glob when iterating over the result
Use Pathname.glob when we want pathname objects
Remove jstalk

Closes #29720.