diff --git a/libs/spandsp/src/g722.c b/libs/spandsp/src/g722.c
index aebe9a575e..f3126e8aa1 100644
--- a/libs/spandsp/src/g722.c
+++ b/libs/spandsp/src/g722.c
@@ -32,6 +32,7 @@
 #include <inttypes.h>
 #include <memory.h>
 #include <stdlib.h>
+#include <string.h>
 #if defined(HAVE_TGMATH_H)
 #include <tgmath.h>
 #endif
diff --git a/libs/spandsp/src/gsm0610_lpc.c b/libs/spandsp/src/gsm0610_lpc.c
index 70e06d4122..c1341882d8 100644
--- a/libs/spandsp/src/gsm0610_lpc.c
+++ b/libs/spandsp/src/gsm0610_lpc.c
@@ -43,6 +43,7 @@
 #include "floating_fudge.h"
 #include <stdlib.h>
 #include <memory.h>
+#include <string.h>
 
 #include "spandsp/telephony.h"
 #include "spandsp/fast_convert.h"
diff --git a/libs/spandsp/src/v8.c b/libs/spandsp/src/v8.c
index 4c5dd43244..4dbe338f72 100644
--- a/libs/spandsp/src/v8.c
+++ b/libs/spandsp/src/v8.c
@@ -33,6 +33,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <memory.h>
+#include <string.h>
 #if defined(HAVE_TGMATH_H)
 #include <tgmath.h>
 #endif