getting abbrev table objects given a string with the same name

[Benjamin Rutt]

How can I do something like the following:

(define-abbrev (concat "c-mode" "-abbrev-table") "foo" "bar" nil)

What I want is to define an abbrev based on an abbrev table name that
is dyamically built.  The problem is, the 1st arg to define-abbrev
must be an abbrev table, not a string.  So, the problem becomes, how
can I get an abbrev table, given a string with the same name.
-- 
Benjamin Rutt