Swiped out of the SDL3 source code.

To compile and install SDL:

    1.  Windows with Visual Studio:
        * Read ./docs/README-visualc.md

        Windows building with mingw-w64 for x86:
        * Run: cmake -S . -B build -DCMAKE_TOOLCHAIN_FILE=build-scripts/cmake-toolchain-mingw64-i686.cmake && cmake --build build && cmake --install build

        Windows building with mingw-w64 for x64:
        * Run: cmake -S . -B build -DCMAKE_TOOLCHAIN_FILE=build-scripts/cmake-toolchain-mingw64-x86_64.cmake && cmake --build build && cmake --install build

        macOS with Xcode:
        * Read docs/README-macos.md

        macOS from the command line:
        * Run: cmake -S . -B build && cmake --build build && cmake --install build

        Linux and other UNIX systems:
        * Run: cmake -S . -B build && cmake --build build && cmake --install build

        Android:
        * Read docs/README-android.md

        iOS:
        * Read docs/README-ios.md

       
Using Cmake:
        * Read docs/README-cmake.md

    2.  Look at the example programs in ./test, and check out the online
        documentation at https://wiki.libsdl.org/

    3.  Join the SDL developer discussions, sign up on
        https://discourse.libsdl.org/
        and go to the development forum
        https://discourse.libsdl.org/c/sdl-development/6

    4.  Sign up for the announcement list through the web interface:
        https://www.libsdl.org/mailing-list.php