*: compile fixes for 64-bit build

diff --git a/console-tools/chvt.c b/console-tools/chvt.c
index 86d3f2d..b1f81a2 100644
--- a/console-tools/chvt.c
+++ b/console-tools/chvt.c
@@ -25,8 +25,9 @@
 	}
 
 	fd = get_console_fd();
-	num = xatoul_range(argv[1], 1, 63);
-	xioctl(fd, VT_ACTIVATE, (void *)num);
-	xioctl(fd, VT_WAITACTIVE, (void *)num);
+	num = xatou_range(argv[1], 1, 63);
+	/* double cast suppresses "cast to ptr from int of different size */
+	xioctl(fd, VT_ACTIVATE, (void *)(ptrdiff_t)num);
+	xioctl(fd, VT_WAITACTIVE, (void *)(ptrdiff_t)num);
 	return EXIT_SUCCESS;
 }