[WIP/RFC] Add unit tests for buffer.c and fileio.c

And on Mountain Lion:

```
$ clang --version
Apple LLVM version 5.1 (clang-503.0.38) (based on LLVM 3.4svn)

$ clang -O2 -c -o foo.o foo.c && nm foo.o
0000000000000048 s EH_frame0
                 U ___bzero
0000000000000090 S _foo
                 U _getchar
0000000000000000 T _main
0000000000000060 S _main.eh
```

At any rate, if you can find *some* way to prevent `foo` from being optimized out, do you see the same results where real memory increases after the array is accessed?