Fix initialization error in read_sysex

src/sysex.c

@@ -28,8 +28,7 @@ sysex_read(midi_io_t *midi, unsigned char *data, size_t len)
     int byte, loop, n, p;
 
     loop = 1;
-    n = 1;
-    p = 0;
+    n = p = 0;
 
     while ( n < len && loop ) {
         if ( (byte = midi_next(midi)) < 0 )