strcasecmp() is defined in strings.h.

src/dmm/metex14.c

@@ -31,6 +31,7 @@
  */
 
 #include <string.h>
+#include <strings.h>
 #include <ctype.h>
 #include <math.h>
 #include <glib.h>

src/hardware/rigol-ds/api.c

@@ -23,6 +23,7 @@
 #include <unistd.h>
 #include <stdlib.h>
 #include <string.h>
+#include <strings.h>
 #include <math.h>
 #include <glib.h>
 #include "libsigrok.h"

src/hardware/scpi-pps/api.c

@@ -18,6 +18,7 @@
  */
 
 #include <string.h>
+#include <strings.h>
 #include "protocol.h"
 
 SR_PRIV struct sr_dev_driver scpi_pps_driver_info;

src/hardware/scpi-pps/profiles.c

@@ -18,6 +18,7 @@
  */
 
 #include <string.h>
+#include <strings.h>
 #include "protocol.h"
 
 #define CH_IDX(x) (1 << x)

src/hardware/scpi-pps/protocol.c

@@ -18,6 +18,7 @@
  */
 
 #include <string.h>
+#include <strings.h>
 #include <stdarg.h>
 #include "protocol.h"
 

src/strutil.c

@@ -21,6 +21,7 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
+#include <strings.h>
 #include <errno.h>
 #include "libsigrok.h"
 #include "libsigrok-internal.h"