SDL_mixer: update for new thread-safe environment functions in SDL3

SDL Commits
1 
From 3d8376d9a869a340bffa5d29f6a1a4d656f68d70 Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Sun, 15 Sep 2024 01:56:40 +0300
Subject: [PATCH] update for new thread-safe environment functions in SDL3

Closes: https://github.com/libsdl-org/SDL_mixer/pull/633
---
 examples/playmus.c          | 2 +-
 src/codecs/music_timidity.c | 2 +-
 src/effects_internal.c      | 2 +-
 src/music.c                 | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/examples/playmus.c b/examples/playmus.c
index 97a67b40..4812b994 100644
--- a/examples/playmus.c
+++ b/examples/playmus.c
@@ -205,7 +205,7 @@ int main(int argc, char *argv[])
     Mix_VolumeMusic(audio_volume);
 
     /* Set the external music player, if any */
-    Mix_SetMusicCMD(SDL_getenv("MUSIC_CMD"));
+    Mix_SetMusicCMD(SDL_GetEnvironmentVariable(SDL_GetEnvironment(), "MUSIC_CMD"));
 
     while (argv[i]) {
         next_track = 0;
diff --git a/src/codecs/music_timidity.c b/src/codecs/music_timidity.c
index 726a7f91..cdbc8a03 100644
--- a/src/codecs/music_timidity.c
+++ b/src/codecs/music_timidity.c
@@ -59,7 +59,7 @@ static int TIMIDITY_Open(const SDL_AudioSpec *spec)
 
     (void) spec;
 
-    cfg = SDL_getenv("TIMIDITY_CFG");
+    cfg = SDL_GetEnvironmentVariable(SDL_GetEnvironment(), "TIMIDITY_CFG");
     if(!cfg) cfg = Mix_GetTimidityCfg();
     if (cfg) {
         return Timidity_Init(cfg); /* env or user override: no other tries */
diff --git a/src/effects_internal.c b/src/effects_internal.c
index a1d81f77..f1108672 100644
--- a/src/effects_internal.c
+++ b/src/effects_internal.c
@@ -37,7 +37,7 @@ int _Mix_effects_max_speed = 0;
 
 void _Mix_InitEffects(void)
 {
-    _Mix_effects_max_speed = (SDL_getenv(MIX_EFFECTSMAXSPEED) != NULL);
+    _Mix_effects_max_speed = (SDL_GetEnvironmentVariable(SDL_GetEnvironment(), MIX_EFFECTSMAXSPEED) != NULL);
 }
 
 void _Mix_DeinitEffects(void)
diff --git a/src/music.c b/src/music.c
index ed42ea02..1efd3812 100644
--- a/src/music.c
+++ b/src/music.c
@@ -1495,7 +1495,7 @@ SDL_bool Mix_SetSoundFonts(const char *paths)
 
 const char* Mix_GetSoundFonts(void)
 {
-    const char *env_paths = SDL_getenv("SDL_SOUNDFONTS");
+    const char *env_paths = SDL_GetEnvironmentVariable(SDL_GetEnvironment(), "SDL_SOUNDFONTS");
     SDL_bool force_env_paths = SDL_GetHintBoolean("SDL_FORCE_SOUNDFONTS", SDL_FALSE);
     if (force_env_paths && (!env_paths || !*env_paths)) {
         force_env_paths = SDL_FALSE;