Missing a PERL module called 'concat'

[Keith Steensma <keith@airways-consulting.com>]

I've installed a very minimum Debian 'testing' system.

I trying to run a perl script that uses a 'concat' function.  I can't 
find it as a built-in function of the language nor can I find it in the 
Debian packages list.

The error is -
Undefined subroutine &main::concat called at ./mbox2maildir.pl line 31.

I've tried to form it into 'libmain-concat-perl' and various other 
wording combinations (for the Debian package search).  I tried another 
script that does the same thing, but I got the same type of error (no 
'concat').  Neither script homepages have any mention of 'something 
special' so I assume that it a 'standard' in other distributions (but 
not Debian).

Anyone have a suggestion?  Keith