[exim] System filter file size too big

Hello Exim users,
We have a relatively large system filter, it just crossed the 1MB
barrier. We are now getting this in the logs, and deliveries are
appearing to be problematic now:

2010-03-26 14:30:37 1NvEIn-000MUt-SL Error in system filter:
/etc/exim/prereview_filters is too big (max 1048576)

I haven't found any variables to increase the maximum allowable file
size, is it a tuneable in the Makefile somewhere?



--
Brent Jones
brent@???