vim-patch:7.4.1988

Problem:    When updating viminfo with file marks there is no time order.
Solution:   Remember the time when a buffer was last used, store marks for
            the most recently used buffers.
ab9c89b68d

As this is a viminfo fix, most of this is irrelevant - the patch has
just been brought across for the creation and updating of buffer's
`b_last_used` properties.

src/nvim/ex_cmds.c

@@ -2670,6 +2670,8 @@ int do_ecmd(
     msg_scrolled_ign = FALSE;
   }
 
+  curbuf->b_last_used = time(NULL);
+
   if (command != NULL)
     do_cmdline(command, NULL, NULL, DOCMD_VERBOSE);