Use stb_vorbis instead of libogg and libvorbis

[VinnyVicious]

Both libogg and libvorbis are huge dependencies and are complex to build across platforms, specially since their bundled CMakeLists.txt are obsolete and rarely updated. No compatibility with other popular build systems or package managers either.

stb_vorbis is a much more portable and would be a great addition to SDL_Mixer.

[Wohlstand]

Some time ago I made the use of stb_vorbis on my form (MixerX) side:

• https://github.com/WohlSoft/SDL-Mixer-X/blob/master/src/codecs/music_ogg_stb.c
• https://github.com/WohlSoft/SDL-Mixer-X/tree/master/src/codecs/stb_vorbis

Note: At me the modified version of stb_vorbis, I made a lot of changes on it, because in its original form it doesn't properly work as a part of Mixer and fails to build on some platforms:

• I replaced all integer types with these are provided by SDL headers
• I replaced all StdC calls with SDL equivalents
• I implemented the SDL_RWops support natively, mainly because given read methods aren't suitable for the case
• I fixed the bug because of inaccurate positioning which is very sensitive for loop tags (reported by one of the users of my projects, and after investigation, I confirmed and fixed it, also I sent the patch to the original version)
• I replaced all C++ single-line comments with C90-friendly multiline comments.

P.S. When using other codes that require libogg (like libFLAC and Opus), it still be used and linked separately.

[slouken]

Added, thanks!

[VinnyVicious]

Thank you!

[slouken]

You're welcome!