link to search.nixos.org instead of pulling package metadata out of pkgs. this
lets us cache docs of a few more modules and provides easier access to package
info from the HTML manual, but makes the manpage slightly less useful since
package description are no longer rendered.
most modules can be evaluated for their documentation in a very
restricted environment that doesn't include all of nixpkgs. this
evaluation can then be cached and reused for subsequent builds, merging
only documentation that has changed into the cached set. since nixos
ships with a large number of modules of which only a few are used in any
given config this can save evaluation a huge percentage of nixos
options available in any given config.
in tests of this caching, despite having to copy most of nixos/, saves
about 80% of the time needed to build the system manual, or about two
second on the machine used for testing. build time for a full system
config shrank from 9.4s to 7.4s, while turning documentation off
entirely shortened the build to 7.1s.
5404595b55 relocated code but kept
one backslah too many, leading to
$ tmux
error creating /run/user/$(id -u)/tmux-1000 (No such file or directory)
/run/user/$UID/ is created by pam_systemd(3) which also populates
XD_RUNTIME_DIR with that value.
Alternatively, TMUX_TMPDIR might simply default to XDG_RUNTIME_DIR
without providing the same directory yet again as default string in
parameter substitution, however such behaviour change is subject to
another patch.
In fact, with `security.polkit.enable = false` systemd_logind(8) fails
to start and /run/user/$UID/ is never created for unprivileged users
in proper login sessions; XDG_RUNTIME_DIR would consequently not be
set either.
Removing the fallback to /run/user/$UID/ would have caused TMUX_TMPDIR
to be empty, which in turn would lead tmux(1) to use /tmp/. This
effectively breaks the idea of isolated sockets entirely while hiding
errors from the user.
This basic module allows you to specify the tmux configuration.
As great as tmux is, some of the defaults are pretty awful, so having a
way to specify the config really helps.
