only .pkgnew and only for user-touched files

Hello, 

after upgrading minor upgrade with pkgbase I found many .pkgsave files such as:
..
/etc/rc.d/noshutdown.pkgsave
/etc/rc.d/mountd.pkgsave
/etc/rc.d/FILESYSTEMS.pkgsave
/etc/rc.d/zfs.pkgsave
...

with changes that do not bothers me:

diff  /etc/rc.d/noshutdown.pkgsave /etc/rc.d/noshutdown
6c6
< # REQUIRE: var
---
> # REQUIRE: FILESYSTEMS
-----

Is it possible during pkgbase upgrade to follow the next logic:

IF configuration/script file is not modified (== identical  to what was installed by package) then silently replace it with new file
ELSE  just save new file as .pkgnew (do not touch existing) and print a note.

Is there already any switches for pkg to do this?

I ask because sshd_config was replaced and server control lost. But master.passwd was keeped. I'm not complaining just missing single logic.

-- 
Best regards,
 Anthony Pankov                          mailto:[email protected]