Mac OS X native port is back up-to-date

After an unanticipated extended hiatus, the native Mac OS X port of Handmade Hero is back up-to-date with Day 219.

Note: Check out the README file for some important instructions on fixing the current clang/llvm porting errors. They are the same problems that Kim pointed out in his GCC/Clang build report here: https://hero.handmadedev.org/code...02-day-211-gcc-clang-build-report

I created a temporary shell script to patch up Casey's code to fix the above errors. It's pretty brittle, but hopefully it won't be needed much longer.

I'll also be doing some code cleanup and will be rearranging the project's directory structures soon to better organize the code and to accommodate Casey's Handmade Hero github repository. That's a nice improvement over downloading the nightly zipped source files.

Jeff