alsa: Clean up device handles, now that hotplug thread cleanup is in place.

src/audio/alsa/SDL_alsa_audio.c

@@ -875,7 +875,6 @@ static void ALSA_HotplugIteration(SDL_bool *has_default_output, SDL_bool *has_de
             //SDL_LogInfo(SDL_LOG_CATEGORY_AUDIO, "ALSA: removing %s device '%s'", dev->iscapture ? "capture" : "output", dev->name);
             next = dev->next;
             SDL_AudioDeviceDisconnected(SDL_FindPhysicalAudioDeviceByHandle(dev->name));
-            SDL_free(dev->name);
             SDL_free(dev);
         }
     }
@@ -910,10 +909,10 @@ static void ALSA_DetectDevices(SDL_AudioDevice **default_output, SDL_AudioDevice
     SDL_bool has_default_output = SDL_FALSE, has_default_capture = SDL_FALSE;
     ALSA_HotplugIteration(&has_default_output, &has_default_capture); // run once now before a thread continues to check.
     if (has_default_output) {
-        *default_output = SDL_AddAudioDevice(/*iscapture=*/SDL_FALSE, "ALSA default output device", NULL, "default");
+        *default_output = SDL_AddAudioDevice(/*iscapture=*/SDL_FALSE, "ALSA default output device", NULL, SDL_strdup("default"));
     }
     if (has_default_capture) {
-        *default_capture = SDL_AddAudioDevice(/*iscapture=*/SDL_TRUE, "ALSA default capture device", NULL, "default");
+        *default_capture = SDL_AddAudioDevice(/*iscapture=*/SDL_TRUE, "ALSA default capture device", NULL, SDL_strdup("default"));
     }
 
 #if SDL_ALSA_HOTPLUG_THREAD
@@ -940,12 +939,16 @@ static void ALSA_DeinitializeStart(void)
     for (dev = hotplug_devices; dev; dev = next) {
         //SDL_LogInfo(SDL_LOG_CATEGORY_AUDIO, "ALSA: at shutdown, removing %s device '%s'", dev->iscapture ? "capture" : "output", dev->name);
         next = dev->next;
-        SDL_free(dev->name);
         SDL_free(dev);
     }
     hotplug_devices = NULL;
 }
 
+static void ALSA_FreeDeviceHandle(SDL_AudioDevice *device)
+{
+    SDL_free(device->handle);
+}
+
 static void ALSA_Deinitialize(void)
 {
     UnloadALSALibrary();
@@ -968,6 +971,7 @@ static SDL_bool ALSA_Init(SDL_AudioDriverImpl *impl)
     impl->WaitCaptureDevice = ALSA_WaitDevice;
     impl->CaptureFromDevice = ALSA_CaptureFromDevice;
     impl->FlushCapture = ALSA_FlushCapture;
+    impl->FreeDeviceHandle = ALSA_FreeDeviceHandle;
 
     impl->HasCaptureSupport = SDL_TRUE;