*further refined s_audio's sample rate detection in the -nogui mode

pd/src/s_audio.c

@@ -521,7 +521,7 @@ t_float sys_getsr(void)
     // proper sample rate entered. Hence we check for this here and avoid
     // the -nogui nonsense where we have to do various workarounds to make
     // sure that audio objects that depend on this call get the proper sr
-    if (sys_dacsr == 0)
+    if (sys_dacsr == 0 && audio_rate > 0)
     {
         sys_dacsr = (t_float)audio_rate;
     }