fix 'void pointer arithmetic' errors.

src/sound_alsa05.c

@@ -171,7 +171,7 @@ static void play(void *b, int i)
 		size_t to_copy = (f < i) ? f : i;
 
 		memcpy(mybuffer_nextfree, b, to_copy);
-		b += to_copy;
+		b = (char *)b + to_copy;
 		mybuffer_nextfree += to_copy;
 		f -= to_copy;
 		i -= to_copy;
@@ -211,4 +211,3 @@ struct sound_driver sound_alsa05 = {
 	bufdump,		/* bufdump */
 	NULL
 };
-

src/sound_coreaudio.c

@@ -233,7 +233,7 @@ static void play(void *b, int i)
 	while (i) {
 		if ((j = write_buffer(b, i)) > 0) {
 			i -= j;
-			b += j;
+			b = (char *)b + j;
 		} else
 			break;
 	}

src/sound_qnx.c

@@ -80,7 +80,7 @@ static void play(void *b, int i)
 	do {
 		if ((j = write(fd_audio, b, i)) > 0) {
 			i -= j;
-			b += j;
+			b = (char *)b + j;
 		} else {
 			break;
 		}