This fixes a regression introduced in
8d7e352a4b. That commit made the false
assumption that utils would have propagated from Nixpkgs to Home
Manager. This commit copies in `escapeSystemdExecArgs` to fix the
immediate issue, perhaps we can pull this in some other way later down
the line.
Before, loading a module would be guarded by an optional platform
condition. This made it possible to avoid loading and evaluating a
module if it did not support the host platform.
Unfortunately, this made it impossible to share a single configuration
between GNU/Linux and Darwin hosts, which some wish to do.
This removes the conditional load and instead inserts host platform
assertions in the modules that are platform specific.
Fixes#1906
