#1 grep regexp too big for large whitelist files

[Anonymous]

I'd love to use whitelight, but there is a problem with large
whitelist files. (I generated my whitelist file from the last
four years of stashed email, and with duplicates removed,
it's a file of some 2341 unique addresses.)

The call to egrep -is -f whitelist generates "egrep: Regular
expression too big". This is a real limit in egrep as far as I
can tell.

Any suggestions?