ref: 611afe7417d63d716531f2ba9f6ae4a2d570a6b8
dir: /external/SDL2/INSTALL.txt/
To compile and install SDL:
    1.  Windows with Visual Studio:
        * Read VisualC.html
        Windows with gcc, either native or cross-compiling:
        * Read the FAQ at https://wiki.libsdl.org/moin.fcg/FAQWindows
        * Run './configure; make; make install'
        Mac OS X with Xcode:
        * Read docs/README-macosx.md
        Mac OS X from the command line:
        * Run './configure; make; make install'
        Linux and other UNIX systems:
        * Run './configure; make; make install'
        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 mailing list by sending E-mail to
    	sdl-request@libsdl.org
        and put "subscribe" in the subject of the message.
        Or alternatively you can use the web interface:
            https://www.libsdl.org/mailing-list.php
That's it!
Sam Lantinga <slouken@libsdl.org>