fixed bug compiling flac without ogg support (SF#1760786: http://sourceforge.net/tracker/index.php?func=detail&aid=1760786&group_id=13478&atid
diff --git a/src/flac/decode.c b/src/flac/decode.c
index 67aff01..1e537c0 100644
--- a/src/flac/decode.c
+++ b/src/flac/decode.c
@@ -276,6 +276,8 @@
 	d->serial_number = serial_number;
 #else
 	(void)is_ogg;
+	(void)use_first_serial_number;
+	(void)serial_number;
 #endif
 
 	d->is_aiff_out = is_aiff_out;
@@ -389,8 +391,6 @@
 		init_status = FLAC__stream_decoder_init_ogg_file(decoder_session->decoder, strcmp(infilename, "-")? infilename : 0, write_callback, metadata_callback, error_callback, /*client_data=*/decoder_session);
 	}
 	else
-#else
-	(void)decode_options;
 #endif
 	{
 		init_status = FLAC__stream_decoder_init_file(decoder_session->decoder, strcmp(infilename, "-")? infilename : 0, write_callback, metadata_callback, error_callback, /*client_data=*/decoder_session);