tools/lib/subcmd/pager.c: do not alias select() params

Use a separate fd set for select()-s exception fds param to fix the
following gcc warning:

  pager.c:36:12: error: passing argument 2 to restrict-qualified parameter aliases with argument 4 [-Werror=restrict]
    select(1, &in, NULL, &in, NULL);
              ^~~        ~~~

Link: http://lkml.kernel.org/r/20180101105626.7168-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tools/lib/subcmd/pager.c

@@ -30,10 +30,13 @@ static void pager_preexec(void)
 	 * have real input
 	 */
 	fd_set in;
+	fd_set exception;
 
 	FD_ZERO(&in);
+	FD_ZERO(&exception);
 	FD_SET(0, &in);
-	select(1, &in, NULL, &in, NULL);
+	FD_SET(0, &exception);
+	select(1, &in, NULL, &exception, NULL);
 
 	setenv("LESS", "FRSX", 0);
 }