diff --git a/libs/spandsp/src/async.c b/libs/spandsp/src/async.c
index 1b7ff8813c..66c6da9ab2 100644
--- a/libs/spandsp/src/async.c
+++ b/libs/spandsp/src/async.c
@@ -103,7 +103,7 @@ SPAN_DECLARE(async_rx_state_t *) async_rx_init(async_rx_state_t *s,
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(void) async_rx_put_bit(void *user_data, int bit)
+SPAN_DECLARE_NONSTD(void) async_rx_put_bit(void *user_data, int bit)
 {
     async_rx_state_t *s;
 
@@ -216,7 +216,7 @@ SPAN_DECLARE(async_tx_state_t *) async_tx_init(async_tx_state_t *s,
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(int) async_tx_get_bit(void *user_data)
+SPAN_DECLARE_NONSTD(int) async_tx_get_bit(void *user_data)
 {
     async_tx_state_t *s;
     int bit;
diff --git a/libs/spandsp/src/silence_gen.c b/libs/spandsp/src/silence_gen.c
index 2423fe6eb2..7af8a366c0 100644
--- a/libs/spandsp/src/silence_gen.c
+++ b/libs/spandsp/src/silence_gen.c
@@ -131,7 +131,7 @@ SPAN_DECLARE(silence_gen_state_t *) silence_gen_init(silence_gen_state_t *s, int
 /* The following dummy routines, to absorb data, don't really have a proper home,
    so they have been put here. */
 
-SPAN_DECLARE(int) span_dummy_rx(void *user_data, const int16_t amp[], int len)
+SPAN_DECLARE_NONSTD(int) span_dummy_rx(void *user_data, const int16_t amp[], int len)
 {
     return 0;
 }
diff --git a/libs/spandsp/src/spandsp/async.h b/libs/spandsp/src/spandsp/async.h
index b6e52c405d..773a99be9a 100644
--- a/libs/spandsp/src/spandsp/async.h
+++ b/libs/spandsp/src/spandsp/async.h
@@ -162,7 +162,7 @@ SPAN_DECLARE(async_tx_state_t *) async_tx_init(async_tx_state_t *s,
     \brief Get the next bit of a transmitted serial bit stream.
     \param user_data An opaque point which must point to a transmitter context.
     \return the next bit, or PUTBIT_END_OF_DATA to indicate the data stream has ended. */
-SPAN_DECLARE(int) async_tx_get_bit(void *user_data);
+SPAN_DECLARE_NONSTD(int) async_tx_get_bit(void *user_data);
 
 /*! Initialise an asynchronous data receiver context.
     \brief Initialise an asynchronous data receiver context.
@@ -191,7 +191,7 @@ SPAN_DECLARE(async_rx_state_t *) async_rx_init(async_rx_state_t *s,
         - SIG_STATUS_TRAINING_SUCCEEDED
         - SIG_STATUS_TRAINING_FAILED
         - SIG_STATUS_END_OF_DATA */
-SPAN_DECLARE(void) async_rx_put_bit(void *user_data, int bit);
+SPAN_DECLARE_NONSTD(void) async_rx_put_bit(void *user_data, int bit);
 
 #if defined(__cplusplus)
 }
diff --git a/libs/spandsp/src/spandsp/complex_vector_float.h b/libs/spandsp/src/spandsp/complex_vector_float.h
index 42cb2a1904..b9ed454424 100644
--- a/libs/spandsp/src/spandsp/complex_vector_float.h
+++ b/libs/spandsp/src/spandsp/complex_vector_float.h
@@ -125,7 +125,7 @@ SPAN_DECLARE(void) cvec_mulf(complexf_t z[], const complexf_t x[], const complex
 SPAN_DECLARE(void) cvec_mul(complex_t z[], const complex_t x[], const complex_t y[], int n);
 
 #if defined(HAVE_LONG_DOUBLE)
-void cvec_mull(complexl_t z[], const complexl_t x[], const complexl_t y[], int n);
+SPAN_DECLARE(void) cvec_mull(complexl_t z[], const complexl_t x[], const complexl_t y[], int n);
 #endif
 
 /*! \brief Find the dot product of two complex float vectors.
diff --git a/libs/spandsp/src/spandsp/silence_gen.h b/libs/spandsp/src/spandsp/silence_gen.h
index 48b471c6e1..f1e8a9995b 100644
--- a/libs/spandsp/src/spandsp/silence_gen.h
+++ b/libs/spandsp/src/spandsp/silence_gen.h
@@ -117,7 +117,7 @@ SPAN_DECLARE(silence_gen_state_t *) silence_gen_init(silence_gen_state_t *s, int
     \param len The length of the signal buffer
     \return 0.
 */
-SPAN_DECLARE(int) span_dummy_rx(void *user_data, const int16_t amp[], int len);
+SPAN_DECLARE_NONSTD(int) span_dummy_rx(void *user_data, const int16_t amp[], int len);
 
 /*! A dummy routine to use as a signal modifier callback, when we aren't
     really trying to process the signal. It just returns without affecting
diff --git a/libs/spandsp/src/spandsp/t30.h b/libs/spandsp/src/spandsp/t30.h
index 614373055f..405ce60da1 100644
--- a/libs/spandsp/src/spandsp/t30.h
+++ b/libs/spandsp/src/spandsp/t30.h
@@ -607,7 +607,7 @@ SPAN_DECLARE(void) t30_front_end_status(void *user_data, int status);
     \brief Get a bit of received non-ECM image data.
     \param user_data An opaque pointer, which must point to the T.30 context.
     \return The next bit to transmit. */
-SPAN_DECLARE(int) t30_non_ecm_get_bit(void *user_data);
+SPAN_DECLARE_NONSTD(int) t30_non_ecm_get_bit(void *user_data);
 
 /*! Get a byte of received non-ECM image data.
     \brief Get a byte of received non-ECM image data.
@@ -627,7 +627,7 @@ SPAN_DECLARE(int) t30_non_ecm_get_chunk(void *user_data, uint8_t buf[], int max_
     \brief Process a bit of received non-ECM image data
     \param user_data An opaque pointer, which must point to the T.30 context.
     \param bit The received bit. */
-SPAN_DECLARE(void) t30_non_ecm_put_bit(void *user_data, int bit);
+SPAN_DECLARE_NONSTD(void) t30_non_ecm_put_bit(void *user_data, int bit);
 
 /*! Process a byte of received non-ECM image data.
     \brief Process a byte of received non-ECM image data
@@ -648,7 +648,7 @@ SPAN_DECLARE(void) t30_non_ecm_put_chunk(void *user_data, const uint8_t buf[], i
     \param msg The HDLC message.
     \param len The length of the message, in octets.
     \param ok TRUE if the frame was received without error. */
-SPAN_DECLARE(void) t30_hdlc_accept(void *user_data, const uint8_t *msg, int len, int ok);
+SPAN_DECLARE_NONSTD(void) t30_hdlc_accept(void *user_data, const uint8_t *msg, int len, int ok);
 
 /*! Report the passage of time to the T.30 engine.
     \brief Report the passage of time to the T.30 engine.
diff --git a/libs/spandsp/src/spandsp/t38_non_ecm_buffer.h b/libs/spandsp/src/spandsp/t38_non_ecm_buffer.h
index cb6f503023..69629b07d4 100644
--- a/libs/spandsp/src/spandsp/t38_non_ecm_buffer.h
+++ b/libs/spandsp/src/spandsp/t38_non_ecm_buffer.h
@@ -93,7 +93,7 @@ SPAN_DECLARE(void) t38_non_ecm_buffer_report_output_status(t38_non_ecm_buffer_st
 /*! \brief Get the next bit of data from a T.38 rate adapting non-ECM buffer context.
     \param user_data The buffer context, cast to a void pointer.
     \return The next bit, or one of the values indicating a change of modem status. */
-SPAN_DECLARE(int) t38_non_ecm_buffer_get_bit(void *user_data);
+SPAN_DECLARE_NONSTD(int) t38_non_ecm_buffer_get_bit(void *user_data);
 
 #if defined(__cplusplus)
 }
diff --git a/libs/spandsp/src/spandsp/v42.h b/libs/spandsp/src/spandsp/v42.h
index 2b43c5a396..dd651c2a2b 100644
--- a/libs/spandsp/src/spandsp/v42.h
+++ b/libs/spandsp/src/spandsp/v42.h
@@ -94,7 +94,7 @@ SPAN_DECLARE(void) lapm_dump(lapm_state_t *s, const uint8_t *frame, int len, int
 
 /*! Accept an HDLC packet
 */
-SPAN_DECLARE(void) lapm_receive(void *user_data, const uint8_t *buf, int len, int ok);
+SPAN_DECLARE_NONSTD(void) lapm_receive(void *user_data, const uint8_t *buf, int len, int ok);
 
 /*! Transmit a LAP.M frame
 */
diff --git a/libs/spandsp/src/t30.c b/libs/spandsp/src/t30.c
index c4c5849005..3e88b0714d 100644
--- a/libs/spandsp/src/t30.c
+++ b/libs/spandsp/src/t30.c
@@ -4986,7 +4986,7 @@ static void t30_non_ecm_rx_status(void *user_data, int status)
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(void) t30_non_ecm_put_bit(void *user_data, int bit)
+SPAN_DECLARE_NONSTD(void) t30_non_ecm_put_bit(void *user_data, int bit)
 {
     t30_state_t *s;
 
@@ -5102,7 +5102,7 @@ SPAN_DECLARE(void) t30_non_ecm_put_chunk(void *user_data, const uint8_t buf[], i
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(int) t30_non_ecm_get_bit(void *user_data)
+SPAN_DECLARE_NONSTD(int) t30_non_ecm_get_bit(void *user_data)
 {
     int bit;
     t30_state_t *s;
@@ -5302,7 +5302,7 @@ static void t30_hdlc_rx_status(void *user_data, int status)
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(void) t30_hdlc_accept(void *user_data, const uint8_t *msg, int len, int ok)
+SPAN_DECLARE_NONSTD(void) t30_hdlc_accept(void *user_data, const uint8_t *msg, int len, int ok)
 {
     t30_state_t *s;
 
diff --git a/libs/spandsp/src/t38_non_ecm_buffer.c b/libs/spandsp/src/t38_non_ecm_buffer.c
index fe09d9e572..faab671338 100644
--- a/libs/spandsp/src/t38_non_ecm_buffer.c
+++ b/libs/spandsp/src/t38_non_ecm_buffer.c
@@ -75,7 +75,7 @@ static void restart_buffer(t38_non_ecm_buffer_state_t *s)
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(int) t38_non_ecm_buffer_get_bit(void *user_data)
+SPAN_DECLARE_NONSTD(int) t38_non_ecm_buffer_get_bit(void *user_data)
 {
     t38_non_ecm_buffer_state_t *s;
     int bit;
diff --git a/libs/spandsp/src/v42.c b/libs/spandsp/src/v42.c
index a00e4faf47..61cd2ca68a 100644
--- a/libs/spandsp/src/v42.c
+++ b/libs/spandsp/src/v42.c
@@ -709,7 +709,7 @@ fprintf(stderr, "Deleting T403 e %d\n", s->t403_timer);
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(void) lapm_receive(void *user_data, const uint8_t *frame, int len, int ok)
+SPAN_DECLARE_NONSTD(void) lapm_receive(void *user_data, const uint8_t *frame, int len, int ok)
 {
     lapm_state_t *s;
     lapm_frame_queue_t *f;