Fix a Coverity warning in SDL Sound

[weirddan455]

Description

First commit fixes the assert macro. The downside of how we're copy + pasting third party libraries into our tree is that we're not using the build system it was written for. HAVE_ASSERT_H is something SDL's build system would have defined. I just removed that macro and always do a #include assert.h since we rely on that header in our other code regardless.

Second commit adds an assert that hopefully Coverity is smart enough to follow. It thinks there is a use after free bug if we're removing from the middle of the linked list in Sound_Quit but that never happens. It's freeing the entire list always removing from the head.

Related issues

#2996

Manual testing

Tested with ripped .ogg files of the Quake sound track. Added the assert and confirmed it does not trigger on quit.

Checklist

Please tick the items as you have addressed them. Don't remove items; leave the ones that are not applicable unchecked.

I have:

• followed the project's contributing guidelines and code of conduct.
• performed a self-review of my code.
• commented on the particularly hard-to-understand areas of my code.
• split my work into well-defined, bisectable commits, and I named my commits well.
• applied the appropriate labels (bug, enhancement, refactoring, documentation, etc.)
• checked that all my commits can be built.
• confirmed that my code does not cause performance regressions (e.g., by running the Quake benchmark).
• added unit tests where applicable to prove the correctness of my code and to avoid future regressions.
• made corresponding changes to the documentation or the website according to the documentation guidelines.
• locally verified my website or documentation changes.

[weirddan455]

I don't see Coverity in the list of CI checks for this PR. @kcgen Does this only happen in the main branch? Is there a way I can test this before merging to see if it actually fixes the warning?

[kcgen]

Nice fix, @weirddan455 !

[kcgen]

I don't see Coverity in the list of CI checks for this PR. @kcgen Does this only happen in the main branch? Is there a way I can test this before merging to see if it actually fixes the warning?

Yes - we have only 7 scans per week; once we use them, PRs will pass through unscanned.

I'll merge your Coverity fixes in quick succession (CI will quickly cancel jobs from prior merges), so this is one way to manually "combine" a handful of small merges and have them only "cost" us a single Coverity scan.

A scan takes about an hour to complete and it does the entire code base.