MacOS DeepMind Problem

I am also following macos deep mind as instructed but keep getting SDL_openg1.h problem. I fixed the Python.h error but am not quite sure if I got it right.

```
$ bazel run :python_random_agent --define graphics=sdl -- \
> --length=10000 --width=640 --height=480
INFO: Analyzed target //:python_random_agent (4 packages loaded, 304 targets configured).
INFO: Found 1 target...
ERROR: /Users/ong/Downloads/lab/BUILD:790:1: C++ compilation of rule '//:game_lib_sdl' failed (Exit 1) wrapped_clang failed: error executing command external/local_config_cc/wrapped_clang '-D_FORTIFY_SOURCE=1' -fstack-protector -fcolor-diagnostics -Wall -Wthread-safety -Wself-assign -fno-omit-frame-pointer -O0 -DDEBUG -iquote . -iquote ... (remaining 76 argument(s) skipped)

Use --sandbox_debug to see verbose messages from the sandbox
In file included from engine/code/renderergl1/tr_world.c:22:
In file included from engine/code/renderergl1/tr_local.h:31:
In file included from engine/code/renderergl1/../renderercommon/tr_common.h:28:
engine/code/renderergl1/../renderercommon/qgl.h:32:11: fatal error: 'SDL_opengl.h' file not found
# include
^~~~~~~~~~~~~~
1 error generated.
Target //:python_random_agent failed to build
Use --verbose_failures to see the command lines of failed build steps.
INFO: Elapsed time: 3.520s, Critical Path: 1.65s
INFO: 26 processes: 26 darwin-sandbox.
FAILED: Build did NOT complete successfully
FAILED: Build did NOT complete successfully
```