Merge branch 'SDL2-update-to-v2.30.0' into 'next'

libs/SDL2/WhatsNew.txt

libs/SDL2/cmake/sdl2-config-version.cmake

libs/SDL2/cmake/sdl2-config.cmake

libs/SDL2/docs/CONTRIBUTING.md

libs/SDL2/docs/README-android.md

libs/SDL2/docs/README-cmake.md

libs/SDL2/docs/README-directfb.md

libs/SDL2/docs/README-dynapi.md

libs/SDL2/docs/README-emscripten.md

libs/SDL2/docs/README-gdk.md

libs/SDL2/docs/README-gesture.md

libs/SDL2/docs/README-ios.md

libs/SDL2/docs/README-linux.md

libs/SDL2/docs/README-macos.md

libs/SDL2/docs/README-macosx.md

libs/SDL2/docs/README-n3ds.md

libs/SDL2/docs/README-nacl.md

libs/SDL2/docs/README-ngage.md

libs/SDL2/docs/README-os2.md

libs/SDL2/docs/README-pandora.md