This is a port of the following changeset from
5.1/storage/innobase to 5.1/storage/innodb_plugin:

  ------------------------------------------------------------
  revno: 3626
  revision-id: vasil.dimov@oracle.com-20101013171859-gi9n558yj89x9v3w
  parent: klewis@mysql.com-20101012175933-ce9kkgl0z8oeqffa
  committer: Vasil Dimov <vasil.dimov@oracle.com>
  branch nick: mysql-5.1-innodb
  timestamp: Wed 2010-10-13 20:18:59 +0300
  message:
    Fix Bug#56143 too many foreign keys causes output of show create table to become invalid
    
    Just remove the check whether the file is "too big".
    A similar code exists in ha_innobase::update_table_comment() but that
    method does not seem to be used.

Also use a CREATE statement with all the FKs instead of ALTERing the
table 550 times because it is faster.