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

lib/libshare/os/linux/nfs.c

@@ -29,7 +29,6 @@
 #include <dirent.h>
 #include <stdio.h>
 #include <string.h>
-#include <strings.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <sys/file.h>

lib/libshare/os/linux/smb.c

@@ -50,7 +50,6 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
-#include <strings.h>
 #include <fcntl.h>
 #include <sys/wait.h>
 #include <unistd.h>