Fixed bug 4525 - Fix crash in ALSA_HotplugThread caused by bad return value check

Anthony Pesch

Fix snd_device_name_hint return value check

According to the ALSA documentation, snd_device_name_hint returns 0 on
success, otherwise a negative error code. The code previously only
considered -1 to be an error, which let other error codes through
resulting in a segfault when hints (which was NULL) was dereferenced

src/audio/alsa/SDL_alsa_audio.c

@@ -788,7 +788,7 @@ ALSA_HotplugThread(void *arg)
         ALSA_Device *seen;
         ALSA_Device *prev;
 
-        if (ALSA_snd_device_name_hint(-1, "pcm", &hints) != -1) {
+        if (ALSA_snd_device_name_hint(-1, "pcm", &hints) == 0) {
             int i, j;
             const char *match = NULL;
             int bestmatch = 0xFFFF;