This patch has been made against cvs+ipv6-1.11.2_2 as supplied in FreeBSD 4.7

The idea is to support a "cache" repository (the one copied to a local machine
by CVSup or CTM) transparently. So that the reads from directory will go
from the local cache repository (and won't overstrain the remote server,
and will be fast too), while the commits and other changes will go into
the remote master repository.

A similar thing may be achieved by checking the files out from the local
repository and doing any modification command with option -d. But that's
troublesome and inconvenient.

This patch allows to deine the following configuration:

# so far everything is as usual
export CVS_RSH=Hssh1
export CVSROOT=user@ncvs.freebsd.org:/home/ncvs
# this is new
export CVSROOTCACHE=/arch/cacheroot

The value specified in CVSROOTCACHE is the local path to the cache
repository. All the check-outs, updates, diffs etc. will be obtained 
from there.  All the check-ins, tagging etc. will go into the master 
repository specified by CVSROOT. Naturally, to see these changes
in the cache repository, it needs to be updated by some outside
means such as CVSup or CTM.

BTW, if there is no chance of conflict between updating the cache
directories and check-outs from it, running check-outs with
"cvs -r" (read-only repository) will make it faster.