nixos/documentation: add option to generate caches

Previously the NixOS-specific configuration for man-db was in the
package itself and /etc/man.conf was completely ignored.
This change moves it to /etc/man_db.conf, making declarative
configuration practical again.

It's now possible to generate the mandb caches for all packages
installed through NixOS `environment.systemPackages` at build-time.
The standard location for the stateful cache (/var/cache/man) is also
configured to allow users to run `mandb` manually if they wish.

Since generating the cache can be expensive the option is off by
default.

0 files changed, 0 insertions, 0 deletions