To compile the software you need GCC and the SDL2 and SDL2_image libraries.
On Mac OSX, GCC comes with XCode and you can install the libraries with brew:
brew install sdl2 sdl2_image
~$ make
gcc -c `pkg-config --cflags sdl2 SDL2_image` main.c
gcc `pkg-config --libs sdl2 SDL2_image` -lm main.o -o main.out
~$ ./main.out
Enjoy!