Going through tutorials at http://www.willusher.io/pages/sdl2/

Plus, making up my own shit.

Warning

There's SDL and SDL2, this caused me a lot of issues as I'd accidentally wind up with the wrong version, or a lib that depended on the wrong version, and tuts/answers are often for the wrong one.

Framework approach to installing SDL2

Initially I couldn't figure out how to get the homebrew thing to work. So I downloaded the DMG from http://libsdl.org/download-2.0.php and copied it into /Library/Frameworks that worked fine, until I wanted to use SDL_gfx, I couldn't figure out how to get them to work together.

Homebrew approach to installing SDL2

brew install sdl2 sdl2_gfx

That installd fine, but you have to manually tell it where to find them when compiling. You can find what to tell the compiler with:

$ sdl2-config --cflags
-I/usr/local/include/SDL2 -D_THREAD_SAFE

$ clang++ -Wall -c -std=c++11 -I ../../include -I/usr/local/include/SDL2 -D_THREAD_SAFE main.cpp -o main.o

And what to tell the linker with:

$ sdl2-config --libs
-L/usr/local/lib -lSDL2

$ clang++ -L/usr/local/lib -lSDL2 -lSDL2_gfx main.o -o SDL_vector

I don't know how you figure out where SDL2_gfx shit is, I just looked in the same place that it told me to find the SDL2 stuff, and then saw they were there, too, so then made a few guesses about what the flags do, and eventually it worked.

Emcc

...I'm not sure that emcc works with libsdl2 or just libsdl, it seemed like the one that it loaded https://github.com/kripken/emscripten/blob/c40c7c218c3cfac5d832607733cf1cbc6ba47dab/tests/hello_world_sdl.cpp#L2 is sdl1 (at least I assume, since the includes are different).