Fixes this error from `nixos-rebuild switch` introduced by #75893:
setting up tmpfiles
[/etc/tmpfiles.d/nixos.conf:7] Invalid age 'yes'.
warning: error(s) occurred while switching to the new configuration
Signed-off-by: Anders Kaseorg <andersk@mit.edu>
In some cases like we've noticed in https://github.com/NixOS/nixpkgs/issues/76169,
having duplicate packages in systemd.packages like
```
systemd.packages = [ gnome-shell gnome-shell gnome-session ];
```
breaks.
Here we use an associative array to ensure no
duplicate paths when we symlink all the units listed
in systemd.packages.
This fixes the dhcpcd issue in https://github.com/NixOS/nixpkgs/issues/76969,
which was exposed by https://github.com/NixOS/nixpkgs/pull/75031
introducing changes in the module ordering and therefore option ordering
too.
The dhcpcd issue would also be fixable by explicitly putting
dhcpcd's paths before others, however it makes more sense for systemd's
default paths to be after all others by default, since they should only
be a fallback, which is how binary finding will work if they come after.
###### Motivation for this change
With space between two options, multiple options just don't work
Looks like xkbOptions then used for generation of xorg.conf.d/00-keyboard.conf.
kbd's man says XkbOptions must be comma-separated without spaces.
https://linux.die.net/man/4/kbd
###### Things done
<!-- Please check what applies. Note that these are not hard requirements but merely serve as information for reviewers. -->
- [ ] Tested using sandboxing ([nix.useSandbox](http://nixos.org/nixos/manual/options.html#opt-nix.useSandbox) on NixOS, or option `sandbox` in [`nix.conf`](http://nixos.org/nix/manual/#sec-conf-file) on non-NixOS linux)
- Built on platform(s)
- [ ] NixOS
- [ ] macOS
- [ ] other Linux distributions
- [ ] Tested via one or more NixOS test(s) if existing and applicable for the change (look inside [nixos/tests](https://github.com/NixOS/nixpkgs/blob/master/nixos/tests))
- [ ] Tested compilation of all pkgs that depend on this change using `nix-shell -p nixpkgs-review --run "nixpkgs-review wip"`
- [ ] Tested execution of all binary files (usually in `./result/bin/`)
- [ ] Determined the impact on package closure size (by running `nix path-info -S` before and after)
- [ ] Ensured that relevant documentation is up to date
- [ ] Fits [CONTRIBUTING.md](https://github.com/NixOS/nixpkgs/blob/master/.github/CONTRIBUTING.md).
###### Notify maintainers
cc @
This reverts commit eec83d41e3e7d9ad5bc1086198d972d55bab1203.
This broke hydra evaluation because with this commit submodule values
are allowed to be paths, however the certmgr module uses `either
(submodule ...) path` in its type, meaning it already used paths for
something else which would now be interpreted as a submodule.
This fixes the patch for nginx to clear the Last-Modified header if a
static file is served from the Nix store.
So far we only used the ETag from the store path, but if the
Last-Modified header is always set to "Thu, 01 Jan 1970 00:00:01 GMT",
Firefox and Chrome/Chromium seem to ignore the ETag and simply use the
cached content instead of revalidating.
Alongside the fix, this also adds a dedicated NixOS VM test, which uses
WebDriver and Firefox to check whether the content is actually served
from the browser's cache and to have a more real-world test case.
