flake: set hostname in mkSystem

hosts/default.nix

@@ -28,12 +28,16 @@ in {
     temperance = mkSystem {
       inherit withSystem;
       system = "x86_64-linux";
+
+      hostname = "temperance";
       modules = mkModulesFor "temperance";
     };
 
     hermit = mkSystem {
       inherit withSystem;
       system = "x86_64-linux";
+
+      hostname = "hermit";
       modules = mkModulesFor "hermit";
     };
   };

modules/system/os/networking/module.nix

@@ -1,11 +1,10 @@
 {config, ...}: let
-  inherit (config.modules.other.system) hostname username;
+  inherit (config.modules.other.system) username;
 in {
   imports = [
     ./networkmanager.nix
   ];
   networking = {
-    hostName = hostname;
     enableIPv6 = true;
     nameservers = [
       # quad9 DNS

parts/lib/builders.nix

@@ -10,6 +10,7 @@
   mkSystem = {
     withSystem,
     system,
+    hostname,
     ...
   } @ args:
     withSystem system (
@@ -30,9 +31,9 @@
             (args.specialArgs or {});
           modules = concatLists [
             # This is used to pre-emptively set the hostPlatform for nixpkgs.
-            # We need a singleton here since we concatenate lists, and a singleton
-            # generates a list with a single element.
+            # Also, we set the system hostname here.
             (singleton {
+              networking.hostName = args.hostname;
               nixpkgs.hostPlatform = mkDefault args.system;
             })