diff --git a/libs/spandsp/src/fsk.c b/libs/spandsp/src/fsk.c
index f3a007fa41..59846a8f3c 100644
--- a/libs/spandsp/src/fsk.c
+++ b/libs/spandsp/src/fsk.c
@@ -169,7 +169,7 @@ SPAN_DECLARE(int) fsk_tx_free(fsk_tx_state_t *s)
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(int) fsk_tx(fsk_tx_state_t *s, int16_t amp[], int len)
+SPAN_DECLARE_NONSTD(int) fsk_tx(fsk_tx_state_t *s, int16_t amp[], int len)
 {
     int sample;
     int bit;
diff --git a/libs/spandsp/src/hdlc.c b/libs/spandsp/src/hdlc.c
index 221debb5e6..0a714f2e70 100644
--- a/libs/spandsp/src/hdlc.c
+++ b/libs/spandsp/src/hdlc.c
@@ -252,7 +252,7 @@ static __inline__ void hdlc_rx_put_bit_core(hdlc_rx_state_t *s)
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(void) hdlc_rx_put_bit(hdlc_rx_state_t *s, int new_bit)
+SPAN_DECLARE_NONSTD(void) hdlc_rx_put_bit(hdlc_rx_state_t *s, int new_bit)
 {
     if (new_bit < 0)
     {
@@ -545,7 +545,7 @@ SPAN_DECLARE(int) hdlc_tx_get_byte(hdlc_tx_state_t *s)
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(int) hdlc_tx_get_bit(hdlc_tx_state_t *s)
+SPAN_DECLARE_NONSTD(int) hdlc_tx_get_bit(hdlc_tx_state_t *s)
 {
     int txbit;
 
diff --git a/libs/spandsp/src/modem_connect_tones.c b/libs/spandsp/src/modem_connect_tones.c
index 1e1566b4f6..656a93a217 100644
--- a/libs/spandsp/src/modem_connect_tones.c
+++ b/libs/spandsp/src/modem_connect_tones.c
@@ -87,7 +87,7 @@ SPAN_DECLARE(const char *) modem_connect_tone_to_str(int tone)
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(int) modem_connect_tones_tx(modem_connect_tones_tx_state_t *s,
+SPAN_DECLARE_NONSTD(int) modem_connect_tones_tx(modem_connect_tones_tx_state_t *s,
                                          int16_t amp[],
                                          int len)
 {
diff --git a/libs/spandsp/src/spandsp/fsk.h b/libs/spandsp/src/spandsp/fsk.h
index 45992d3d38..1e34ef1f3e 100644
--- a/libs/spandsp/src/spandsp/fsk.h
+++ b/libs/spandsp/src/spandsp/fsk.h
@@ -175,7 +175,7 @@ SPAN_DECLARE(void) fsk_tx_set_modem_status_handler(fsk_tx_state_t *s, modem_tx_s
     \param len The number of samples to be generated.
     \return The number of samples actually generated.
 */
-SPAN_DECLARE(int) fsk_tx(fsk_tx_state_t *s, int16_t amp[], int len);
+SPAN_DECLARE_NONSTD(int) fsk_tx(fsk_tx_state_t *s, int16_t amp[], int len);
 
 /*! Get the current received signal power.
     \param s The modem context.
diff --git a/libs/spandsp/src/spandsp/hdlc.h b/libs/spandsp/src/spandsp/hdlc.h
index 47ae1ca164..fae8fc5360 100644
--- a/libs/spandsp/src/spandsp/hdlc.h
+++ b/libs/spandsp/src/spandsp/hdlc.h
@@ -154,7 +154,7 @@ SPAN_DECLARE(int) hdlc_rx_get_stats(hdlc_rx_state_t *s,
     \param s A pointer to an HDLC receiver context.
     \param new_bit The bit.
 */
-SPAN_DECLARE(void) hdlc_rx_put_bit(hdlc_rx_state_t *s, int new_bit);
+SPAN_DECLARE_NONSTD(void) hdlc_rx_put_bit(hdlc_rx_state_t *s, int new_bit);
 
 /*! \brief Put a byte of data to an HDLC receiver.
     \param s A pointer to an HDLC receiver context.
@@ -228,7 +228,7 @@ SPAN_DECLARE(int) hdlc_tx_abort(hdlc_tx_state_t *s);
     \param s A pointer to an HDLC transmitter context.
     \return The next bit for transmission.
 */
-SPAN_DECLARE(int) hdlc_tx_get_bit(hdlc_tx_state_t *s);
+SPAN_DECLARE_NONSTD(int) hdlc_tx_get_bit(hdlc_tx_state_t *s);
 
 /*! \brief Get the next byte for transmission.
     \param s A pointer to an HDLC transmitter context.
diff --git a/libs/spandsp/src/spandsp/modem_connect_tones.h b/libs/spandsp/src/spandsp/modem_connect_tones.h
index a1c13b7e59..0f42e67575 100644
--- a/libs/spandsp/src/spandsp/modem_connect_tones.h
+++ b/libs/spandsp/src/spandsp/modem_connect_tones.h
@@ -125,7 +125,7 @@ SPAN_DECLARE(int) modem_connect_tones_tx_free(modem_connect_tones_tx_state_t *s)
     \param len The number of samples to generate.
     \return The number of samples generated.
 */
-SPAN_DECLARE(int) modem_connect_tones_tx(modem_connect_tones_tx_state_t *s,
+SPAN_DECLARE_NONSTD(int) modem_connect_tones_tx(modem_connect_tones_tx_state_t *s,
                                          int16_t amp[],
                                          int len);
 
diff --git a/libs/spandsp/src/spandsp/tone_generate.h b/libs/spandsp/src/spandsp/tone_generate.h
index 4ca3fadbb6..683005594f 100644
--- a/libs/spandsp/src/spandsp/tone_generate.h
+++ b/libs/spandsp/src/spandsp/tone_generate.h
@@ -88,7 +88,7 @@ SPAN_DECLARE(void) make_tone_gen_descriptor(tone_gen_descriptor_t *s,
                                             int d4,
                                             int repeat);
 
-SPAN_DECLARE(int) tone_gen(tone_gen_state_t *s, int16_t amp[], int max_samples);
+SPAN_DECLARE_NONSTD(int) tone_gen(tone_gen_state_t *s, int16_t amp[], int max_samples);
 
 SPAN_DECLARE(tone_gen_state_t *) tone_gen_init(tone_gen_state_t *s, tone_gen_descriptor_t *t);
 
diff --git a/libs/spandsp/src/spandsp/v27ter_tx.h b/libs/spandsp/src/spandsp/v27ter_tx.h
index 3323e9a903..f0f74afb76 100644
--- a/libs/spandsp/src/spandsp/v27ter_tx.h
+++ b/libs/spandsp/src/spandsp/v27ter_tx.h
@@ -141,7 +141,7 @@ SPAN_DECLARE(void) v27ter_tx_set_modem_status_handler(v27ter_tx_state_t *s, mode
     \param len The number of samples to be generated.
     \return The number of samples actually generated.
 */
-SPAN_DECLARE(int) v27ter_tx(v27ter_tx_state_t *s, int16_t amp[], int len);
+SPAN_DECLARE_NONSTD(int) v27ter_tx(v27ter_tx_state_t *s, int16_t amp[], int len);
 
 #if defined(__cplusplus)
 }
diff --git a/libs/spandsp/src/spandsp/v29tx.h b/libs/spandsp/src/spandsp/v29tx.h
index c0760aeb77..64fd5790a5 100644
--- a/libs/spandsp/src/spandsp/v29tx.h
+++ b/libs/spandsp/src/spandsp/v29tx.h
@@ -172,7 +172,7 @@ SPAN_DECLARE(void) v29_tx_set_modem_status_handler(v29_tx_state_t *s, modem_tx_s
     \param len The number of samples to be generated.
     \return The number of samples actually generated.
 */
-SPAN_DECLARE(int) v29_tx(v29_tx_state_t *s, int16_t amp[], int len);
+SPAN_DECLARE_NONSTD(int) v29_tx(v29_tx_state_t *s, int16_t amp[], int len);
 
 #if defined(__cplusplus)
 }
diff --git a/libs/spandsp/src/tone_generate.c b/libs/spandsp/src/tone_generate.c
index 7d81ef37c1..2492072389 100644
--- a/libs/spandsp/src/tone_generate.c
+++ b/libs/spandsp/src/tone_generate.c
@@ -143,7 +143,7 @@ SPAN_DECLARE(int) tone_gen_free(tone_gen_state_t *s)
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(int) tone_gen(tone_gen_state_t *s, int16_t amp[], int max_samples)
+SPAN_DECLARE_NONSTD(int) tone_gen(tone_gen_state_t *s, int16_t amp[], int max_samples)
 {
     int samples;
     int limit;
diff --git a/libs/spandsp/src/v27ter_tx.c b/libs/spandsp/src/v27ter_tx.c
index cca8a8b854..56fc9a3053 100644
--- a/libs/spandsp/src/v27ter_tx.c
+++ b/libs/spandsp/src/v27ter_tx.c
@@ -244,7 +244,7 @@ static complexf_t getbaud(v27ter_tx_state_t *s)
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(int) v27ter_tx(v27ter_tx_state_t *s, int16_t amp[], int len)
+SPAN_DECLARE_NONSTD(int) v27ter_tx(v27ter_tx_state_t *s, int16_t amp[], int len)
 {
 #if defined(SPANDSP_USE_FIXED_POINT)
     complexi_t x;
diff --git a/libs/spandsp/src/v29tx.c b/libs/spandsp/src/v29tx.c
index ff1a2f9e8d..c51c76a497 100644
--- a/libs/spandsp/src/v29tx.c
+++ b/libs/spandsp/src/v29tx.c
@@ -202,7 +202,7 @@ static __inline__ complexf_t getbaud(v29_tx_state_t *s)
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(int) v29_tx(v29_tx_state_t *s, int16_t amp[], int len)
+SPAN_DECLARE_NONSTD(int) v29_tx(v29_tx_state_t *s, int16_t amp[], int len)
 {
 #if defined(SPANDSP_USE_FIXED_POINT)
     complexi_t x;