Copy the SDL_rotozoom.* files to your SDL include directory,
if you don't already have them.

To compile use something like: 
"cc -lSDL -lSDL_image -pedantic -O2 -o shim shim.c" 
and omit or use any other options you desire. The options -pedantic and -O2 
are probably pretty pointless, but I used it for the sake of it. You can 
also try to use the provided "compile_shim.sh" script, which may or may not 
work for you.