Extra support for some archive types

[korsar182 at gmail.com]

Ralph Seichter <abbot at monksofcool.net> писал(а) в своём письме Sat, 10 Aug  
2019 00:05:12 +0300:

> * korsar:
>
>> 1) ACE has no support at all, need to add it
>
> Not having seen ACE archives in the wild for more than 10 years, I don't
> think so. Besides, to my knowledge ACE is a proprietary format with a
> Windows focus and a license that does not permit including it in free
> software.
>
>> 2) gzip - gzip -d command changes original file names of extracted
>> files, [...] 7z, please.
>
> You can adjust filetype-to-decoder mappings in your amavisd.conf if you
> don't like the defaults.
>
> -Ralph

I mean 7zip supports 35 archive type, any of them may be used to hide  
ransomware in the .rar or .zip file and opened by end user. So the mail  
system is only half protected.

How I can make filetype-to-decoder mappings in amavisd.conf?
Set "$gzip       = '7z';"?