The present changes are a direct copy-paste from https://github.com/zeldaret/mm/pull/1850
This fixes building on macos due to a kinda specific issue with Apple clang.
When trying to build on Macos (specifically MacOS 12, Monteray with Apple clang 13.0.0 (clang-1300.0.29.30), idk if other versions have this issue too) `make` stops with the following error from `atblgen`:
```
Failed to match line 1: ""
regexec error: "regexec() failed to match"
Error: Malformed build/n64-us/assets/audio/sequence_order.in?
```
`atblgen` makes the assumption that the `sequence_order.in` file has no extra data, spaces, empty lines, etc. but the file somehow ends up having empty lines between each line on macos.
This file is created by using the C preprocessor to process `include/tables/sequence_table.h`.
In normal circumstances this file should look like this snip,
```
(Sequence_0,NA_BGM_GENERAL_SFX)
(Sequence_1,NA_BGM_AMBIENCE)
(Sequence_2,NA_BGM_TERMINA_FIELD)
(Sequence_3,NA_BGM_CHASE)
(Sequence_4,NA_BGM_MAJORAS_THEME)
```
but it ends up looking like this instead
```
(Sequence_0,NA_BGM_GENERAL_SFX)
(Sequence_1,NA_BGM_AMBIENCE)
(Sequence_2,NA_BGM_TERMINA_FIELD)
(Sequence_3,NA_BGM_CHASE)
(Sequence_4,NA_BGM_MAJORAS_THEME)
```
which `atblgen` doesn't like.
I believe this happens because there are lines with comments between each macro in [`sequence_table.h`](https://github.com/zeldaret/mm/blob/0877ce4adf28a8e73e05c3c58682273b8bf28749/include/tables/sequence_table.h) and for some reason this Apple clang version decided to preserve those empty lines
The fix just makes `atblgen` skip empty lines.
I threw `atblgen` to valgrind to check the fix was working as intended and noted a bunch of memory that was being free before exit, so I fixed them.
I also noted the tools/audio makefile was not using `OPTFLAGS` when building those tools, so I fixed that too.