Forbid b{copy,zero,cmp}(). Don't include <strings.h> for <string.h>

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #12996

tests/zfs-tests/tests/functional/checksum/skein_test.c

@@ -34,7 +34,7 @@
 
 #include <sys/skein.h>
 #include <stdlib.h>
-#include <strings.h>
+#include <string.h>
 #include <stdio.h>
 #include <sys/time.h>
 #include <sys/stdtypes.h>

tests/zfs-tests/tests/functional/ctime/ctime.c

@@ -38,7 +38,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
-#include <strings.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <libgen.h>

tests/zfs-tests/tests/functional/hkdf/hkdf_test.c

@@ -18,13 +18,11 @@
  */
 
 #include <stdio.h>
-#include <strings.h>
+#include <string.h>
 #include <sys/crypto/icp.h>
 #include <sys/sha2.h>
 #include <sys/hkdf.h>
 
-#define	NELEMS(x)  (sizeof (x) / sizeof ((x)[0]))
-
 /*
  * Byte arrays are given as char pointers so that they
  * can be specified as strings.
@@ -214,7 +212,7 @@ main(void)
 
 	icp_init();
 
-	for (i = 0; i < NELEMS(test_vectors); i++) {
+	for (i = 0; i < ARRAY_SIZE(test_vectors); i++) {
 		ret = run_test(i, &test_vectors[i]);
 		if (ret != 0)
 			break;