Adding makemandb as build tool for man.db

On lower powered (and particularly lower memory boxes), the makemandb
on first boot after install can run for some time and significantly
affect the performance of the system (in extreme cases for several
hours).

We already have makewhatis as a build tool. What do people think of
adding makemandb and including man.db to the distribution (potentially
optionally).

The downside is it would around double the size of man.tgz if enabled,
but it would avoid a particularly bad first impression for anyone
installing on an smaller boxes such as embedded arm/x86 (so not just
vax/m68k/sh3/sparc users :-p)

Thanks

David