diff --git a/sys/src/cmd/audio/libFLAC/bitbuffer.c b/sys/src/cmd/audio/libFLAC/bitbuffer.c
index d31976a51..312ed7f96 100644
--- a/sys/src/cmd/audio/libFLAC/bitbuffer.c
+++ b/sys/src/cmd/audio/libFLAC/bitbuffer.c
@@ -267,7 +267,7 @@ static FLAC__bool bitbuffer_read_from_client_(FLAC__BitBuffer *bb, FLAC__bool (*
  *
  ***********************************************************************/
 
-FLAC__BitBuffer *FLAC__bitbuffer_new()
+FLAC__BitBuffer *FLAC__bitbuffer_new(void)
 {
 	FLAC__BitBuffer *bb = (FLAC__BitBuffer*)calloc(1, sizeof(FLAC__BitBuffer));
 
diff --git a/sys/src/cmd/audio/libFLAC/file_decoder.c b/sys/src/cmd/audio/libFLAC/file_decoder.c
index 94e5c9456..c5ea3e2bf 100644
--- a/sys/src/cmd/audio/libFLAC/file_decoder.c
+++ b/sys/src/cmd/audio/libFLAC/file_decoder.c
@@ -51,7 +51,7 @@
  ***********************************************************************/
 
 static void set_defaults_(FLAC__FileDecoder *decoder);
-static FILE *get_binary_stdin_();
+static FILE *get_binary_stdin_(void);
 static FLAC__SeekableStreamDecoderReadStatus read_callback_(const FLAC__SeekableStreamDecoder *decoder, FLAC__byte buffer[], unsigned *bytes, void *client_data);
 static FLAC__SeekableStreamDecoderSeekStatus seek_callback_(const FLAC__SeekableStreamDecoder *decoder, FLAC__uint64 absolute_byte_offset, void *client_data);
 static FLAC__SeekableStreamDecoderTellStatus tell_callback_(const FLAC__SeekableStreamDecoder *decoder, FLAC__uint64 *absolute_byte_offset, void *client_data);
@@ -95,13 +95,15 @@ FLAC_API const char * const FLAC__FileDecoderStateString[] = {
 	"FLAC__FILE_DECODER_UNINITIALIZED"
 };
 
+FLAC_API FLAC__SeekableStreamDecoder *FLAC__seekable_stream_decoder_new(void);
+
 /***********************************************************************
  *
  * Class constructor/destructor
  *
  ***********************************************************************/
 
-FLAC_API FLAC__FileDecoder *FLAC__file_decoder_new()
+FLAC_API FLAC__FileDecoder *FLAC__file_decoder_new(void)
 {
 	FLAC__FileDecoder *decoder;
 
@@ -567,7 +569,7 @@ void set_defaults_(FLAC__FileDecoder *decoder)
 /*
  * This will forcibly set stdin to binary mode (for OSes that require it)
  */
-FILE *get_binary_stdin_()
+FILE *get_binary_stdin_(void)
 {
 	/* if something breaks here it is probably due to the presence or
 	 * absence of an underscore before the identifiers 'setmode',
diff --git a/sys/src/cmd/audio/libFLAC/file_encoder.c b/sys/src/cmd/audio/libFLAC/file_encoder.c
index e1ab7350d..bc899b56a 100644
--- a/sys/src/cmd/audio/libFLAC/file_encoder.c
+++ b/sys/src/cmd/audio/libFLAC/file_encoder.c
@@ -91,6 +91,7 @@ FLAC_API const char * const FLAC__FileEncoderStateString[] = {
 	"FLAC__FILE_ENCODER_UNINITIALIZED"
 };
 
+FLAC_API FLAC__SeekableStreamEncoder *FLAC__seekable_stream_encoder_new(void);
 
 /***********************************************************************
  *
diff --git a/sys/src/cmd/audio/libFLAC/metadata_iterators.c b/sys/src/cmd/audio/libFLAC/metadata_iterators.c
index 45e5c3fe3..99029b3ab 100644
--- a/sys/src/cmd/audio/libFLAC/metadata_iterators.c
+++ b/sys/src/cmd/audio/libFLAC/metadata_iterators.c
@@ -157,6 +157,8 @@ typedef struct {
 	FLAC__StreamMetadata *object;
 } level0_client_data;
 
+FLAC_API FLAC__FileDecoder *FLAC__file_decoder_new(void);
+
 FLAC_API FLAC__bool FLAC__metadata_get_streaminfo(const char *filename, FLAC__StreamMetadata *streaminfo)
 {
 	level0_client_data cd;
@@ -339,7 +341,7 @@ FLAC_API const char * const FLAC__Metadata_SimpleIteratorStatusString[] = {
 };
 
 
-FLAC_API FLAC__Metadata_SimpleIterator *FLAC__metadata_simple_iterator_new()
+FLAC_API FLAC__Metadata_SimpleIterator *FLAC__metadata_simple_iterator_new(void)
 {
 	FLAC__Metadata_SimpleIterator *iterator = (FLAC__Metadata_SimpleIterator*)calloc(1, sizeof(FLAC__Metadata_SimpleIterator));
 
@@ -846,7 +848,7 @@ FLAC_API const char * const FLAC__Metadata_ChainStatusString[] = {
 };
 
 
-static FLAC__Metadata_Node *node_new_()
+static FLAC__Metadata_Node *node_new_(void)
 {
 	return (FLAC__Metadata_Node*)calloc(1, sizeof(FLAC__Metadata_Node));
 }
diff --git a/sys/src/cmd/audio/libFLAC/metadata_object.c b/sys/src/cmd/audio/libFLAC/metadata_object.c
index 589357b67..886a17c77 100644
--- a/sys/src/cmd/audio/libFLAC/metadata_object.c
+++ b/sys/src/cmd/audio/libFLAC/metadata_object.c
@@ -1085,7 +1085,7 @@ FLAC_API int FLAC__metadata_object_vorbiscomment_remove_entries_matching(FLAC__S
 	return ok? (int)matching : -1;
 }
 
-FLAC_API FLAC__StreamMetadata_CueSheet_Track *FLAC__metadata_object_cuesheet_track_new()
+FLAC_API FLAC__StreamMetadata_CueSheet_Track *FLAC__metadata_object_cuesheet_track_new(void)
 {
 	return (FLAC__StreamMetadata_CueSheet_Track*)calloc(1, sizeof(FLAC__StreamMetadata_CueSheet_Track));
 }
diff --git a/sys/src/cmd/audio/libFLAC/seekable_stream_decoder.c b/sys/src/cmd/audio/libFLAC/seekable_stream_decoder.c
index c0d8d0be2..b66d14924 100644
--- a/sys/src/cmd/audio/libFLAC/seekable_stream_decoder.c
+++ b/sys/src/cmd/audio/libFLAC/seekable_stream_decoder.c
@@ -134,7 +134,7 @@ FLAC_API const char * const FLAC__SeekableStreamDecoderLengthStatusString[] = {
  *
  ***********************************************************************/
 
-FLAC_API FLAC__SeekableStreamDecoder *FLAC__seekable_stream_decoder_new()
+FLAC_API FLAC__SeekableStreamDecoder *FLAC__seekable_stream_decoder_new(void)
 {
 	FLAC__SeekableStreamDecoder *decoder;
 
diff --git a/sys/src/cmd/audio/libFLAC/seekable_stream_encoder.c b/sys/src/cmd/audio/libFLAC/seekable_stream_encoder.c
index ac3ed18ec..fd3d815aa 100644
--- a/sys/src/cmd/audio/libFLAC/seekable_stream_encoder.c
+++ b/sys/src/cmd/audio/libFLAC/seekable_stream_encoder.c
@@ -103,6 +103,7 @@ FLAC_API const char * const FLAC__SeekableStreamEncoderTellStatusString[] = {
 	"FLAC__SEEKABLE_STREAM_ENCODER_TELL_STATUS_ERROR"
 };
 
+FLAC_API FLAC__StreamEncoder *FLAC__stream_encoder_new(void);
 
 /***********************************************************************
  *
@@ -110,7 +111,7 @@ FLAC_API const char * const FLAC__SeekableStreamEncoderTellStatusString[] = {
  *
  ***********************************************************************/
 
-FLAC_API FLAC__SeekableStreamEncoder *FLAC__seekable_stream_encoder_new()
+FLAC_API FLAC__SeekableStreamEncoder *FLAC__seekable_stream_encoder_new(void)
 {
 	FLAC__SeekableStreamEncoder *encoder;
 
diff --git a/sys/src/cmd/audio/libFLAC/stream_decoder.c b/sys/src/cmd/audio/libFLAC/stream_decoder.c
index 4b1c5776f..09f0f832e 100644
--- a/sys/src/cmd/audio/libFLAC/stream_decoder.c
+++ b/sys/src/cmd/audio/libFLAC/stream_decoder.c
@@ -174,6 +174,8 @@ FLAC_API const char * const FLAC__StreamDecoderErrorStatusString[] = {
 	"FLAC__STREAM_DECODER_ERROR_STATUS_FRAME_CRC_MISMATCH"
 };
 
+FLAC__BitBuffer *FLAC__bitbuffer_new(void);
+
 /***********************************************************************
  *
  * Class constructor/destructor
diff --git a/sys/src/cmd/audio/libFLAC/stream_encoder.c b/sys/src/cmd/audio/libFLAC/stream_encoder.c
index ca033b067..554669650 100644
--- a/sys/src/cmd/audio/libFLAC/stream_encoder.c
+++ b/sys/src/cmd/audio/libFLAC/stream_encoder.c
@@ -434,12 +434,14 @@ FLAC_API const char * const FLAC__StreamEncoderWriteStatusString[] = {
 	"FLAC__STREAM_ENCODER_WRITE_STATUS_FATAL_ERROR"
 };
 
+FLAC__BitBuffer *FLAC__bitbuffer_new(void);
+
 /***********************************************************************
  *
  * Class constructor/destructor
  *
  */
-FLAC_API FLAC__StreamEncoder *FLAC__stream_encoder_new()
+FLAC_API FLAC__StreamEncoder *FLAC__stream_encoder_new(void)
 {
 	FLAC__StreamEncoder *encoder;
 	unsigned i;