SDL_mixer: remove obsolete enum values MUS_MODPLUG_UNUSED and MUS_MP3_MAD_UNUSED.

SDL Commits
1 
From 4970bacc5954237037b00f8d2797e23b07782b2f Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Mon, 10 Mar 2025 18:36:28 +0300
Subject: [PATCH] remove obsolete enum values MUS_MODPLUG_UNUSED and
 MUS_MP3_MAD_UNUSED.

---
 examples/playmus.c             | 2 --
 include/SDL3_mixer/SDL_mixer.h | 2 --
 2 files changed, 4 deletions(-)

diff --git a/examples/playmus.c b/examples/playmus.c
index 1773bda95..b833bf6d8 100644
--- a/examples/playmus.c
+++ b/examples/playmus.c
@@ -223,7 +223,6 @@ int main(int argc, char *argv[])
             typ = "WAV";
             break;
         case MUS_MOD:
-        case MUS_MODPLUG_UNUSED:
             typ = "MOD";
             break;
         case MUS_FLAC:
@@ -236,7 +235,6 @@ int main(int argc, char *argv[])
             typ = "OGG Vorbis";
             break;
         case MUS_MP3:
-        case MUS_MP3_MAD_UNUSED:
             typ = "MP3";
             break;
         case MUS_OPUS:
diff --git a/include/SDL3_mixer/SDL_mixer.h b/include/SDL3_mixer/SDL_mixer.h
index 71ebdb8ab..b912882e0 100644
--- a/include/SDL3_mixer/SDL_mixer.h
+++ b/include/SDL3_mixer/SDL_mixer.h
@@ -219,9 +219,7 @@ typedef enum Mix_MusicType {
     MUS_MID,
     MUS_OGG,
     MUS_MP3,
-    MUS_MP3_MAD_UNUSED,
     MUS_FLAC,
-    MUS_MODPLUG_UNUSED,
     MUS_OPUS,
     MUS_WAVPACK,
     MUS_GME