Fix some more undefined behaviour

As #784 notified me of
undefined behaviour going undetected by the fuzzers, I ran the test
suite with the full undefined behaviour sanitizer enabled.

There is one bit of undefined behaviour that I cannot fix,
FLAC__metadata_get_picture allows a picture type of -1 to mean all,
but this isn't part of the enum.

src/libFLAC/include/private/ogg_encoder_aspect.h

@@ -58,7 +58,7 @@ void FLAC__ogg_encoder_aspect_set_defaults(FLAC__OggEncoderAspect *aspect);
 FLAC__bool FLAC__ogg_encoder_aspect_init(FLAC__OggEncoderAspect *aspect);
 void FLAC__ogg_encoder_aspect_finish(FLAC__OggEncoderAspect *aspect);
 
-typedef FLAC__StreamEncoderWriteStatus (*FLAC__OggEncoderAspectWriteCallbackProxy)(const void *encoder, const FLAC__byte buffer[], size_t bytes, uint32_t samples, uint32_t current_frame, void *client_data);
+typedef FLAC__StreamEncoderWriteStatus (*FLAC__OggEncoderAspectWriteCallbackProxy)(const FLAC__StreamEncoder *encoder, const FLAC__byte buffer[], size_t bytes, uint32_t samples, uint32_t current_frame, void *client_data);
 
 FLAC__StreamEncoderWriteStatus FLAC__ogg_encoder_aspect_write_callback_wrapper(FLAC__OggEncoderAspect *aspect, const FLAC__byte buffer[], size_t bytes, uint32_t samples, uint32_t current_frame, FLAC__bool is_last_block, FLAC__OggEncoderAspectWriteCallbackProxy write_callback, void *encoder, void *client_data);
 #endif

src/share/grabbag/cuesheet.c

@@ -332,7 +332,7 @@ static FLAC__bool local__cuesheet_parse_(FILE *file, const char **error_message,
 			}
 			else if(0 == FLAC__STRCASECMP(field, "INDEX")) {
 				FLAC__int64 xx;
-				FLAC__StreamMetadata_CueSheet_Track *track = &cs->tracks[cs->num_tracks-1];
+				FLAC__StreamMetadata_CueSheet_Track *track;
 				if(in_track_num < 0) {
 					*error_message = "found INDEX before any TRACK";
 					return false;
@@ -347,6 +347,7 @@ static FLAC__bool local__cuesheet_parse_(FILE *file, const char **error_message,
 					return false;
 				}
 				FLAC__ASSERT(cs->num_tracks > 0);
+				track = &cs->tracks[cs->num_tracks-1];
 				if(track->num_indices == 0) {
 					/* it's the first index point of the track */
 					if(in_index_num > 1) {

src/test_streams/main.c

@@ -125,11 +125,11 @@ static FLAC__bool write_little_endian_uint64(FILE *f, FLAC__uint64 x)
 static FLAC__bool write_big_endian(FILE *f, FLAC__int32 x, size_t bytes)
 {
 	if(bytes < 4)
-		x <<= 8*(4-bytes);
+		x = (uint32_t)x << 8*(4-bytes);
 	while(bytes) {
 		if(fputc(x>>24, f) == EOF)
 			return false;
-		x <<= 8;
+		x = (uint32_t)x << 8;
 		bytes--;
 	}
 	return true;
@@ -1057,7 +1057,7 @@ static FLAC__bool write_simple_wavex_header (FILE * f, unsigned samplerate, unsi
 static FLAC__bool generate_noisy_sine(void)
 {
 	FILE *f;
-	int64_t randstate = 0x1243456;
+	uint64_t randstate = 0x1243456;
 	double sample, last_val = 0.0;
 	int k;
 	int seconds = 300;