[exim] Procmail & exim delivery errors to a full mailbox

Hi All,

We're using Exim 4.52 with procmail 3.22 with procmail set as
the MDA. Filesystem quotas are being used to control mailbox
size, but this is resulting in an undesirable error.

If a user is over quota and procmail has failed to deliver a
message, and the message finally times out of the queue, the
sender of the original message gets a "local delivery failed: retry timeout exceeded"
error.