man is broken and use.perl script shows the problem

It turns out that if there are too many entries in /etc/manpath.config
man will core dump.  I sent a trace of this already.  I had done one too
many portupgrade -f that included perl.  The use.perl script blindly
adds additional lines

# -- use.perl generated line -- #
OPTIONAL_MANPATH        /usr/local/lib/perl5/5.8.5/man
OPTIONAL_MANPATH        /usr/local/lib/perl5/5.8.5/perl/man

and I ended up with a bunch of these.  You can reproduce the problem by
simply adding enough duplicates of these lines into /etc/manpath.config.

use.perl does the same thing with /etc/make.conf but at least in that
case it is harmless.

Cheers,
Sean