Use systemd-boot instead of gummiboot

Gummiboot is part of systemd now so we may as well use it.

nixos/modules/system/boot/loader/efi.nix

···
 
 {
   options.boot.loader.efi = {
+
     canTouchEfiVariables = mkOption {
       default = false;
-
       type = types.bool;
-
-      description = "Whether or not the installation process should modify efi boot variables.";
+      description = "Whether the installation process is allowed to modify EFI boot variables.";
     };
 
     efiSysMountPoint = mkOption {
       default = "/boot";
-
       type = types.str;
-
       description = "Where the EFI System Partition is mounted.";
     };
   };

nixos/modules/system/boot/loader/grub/grub.nix

···
         }
         {
           assertion = if args.efiSysMountPoint == null then true else hasPrefix "/" args.efiSysMountPoint;
-          message = "Efi paths must be absolute, not ${args.efiSysMountPoint}";
+          message = "EFI paths must be absolute, not ${args.efiSysMountPoint}";
         }
       ] ++ flip map args.devices (device: {
         assertion = device == "nodev" || hasPrefix "/" device;

nixos/modules/system/boot/loader/gummiboot/gummiboot-builder.py

···
         if not path in known_paths:
             os.unlink(path)
 
-parser = argparse.ArgumentParser(description='Update NixOS-related gummiboot files')
+parser = argparse.ArgumentParser(description='Update NixOS-related systemd-boot files')
 parser.add_argument('default_config', metavar='DEFAULT-CONFIG', help='The default NixOS config to boot')
 args = parser.parse_args()
 
 # We deserve our own env var!
 if os.getenv("NIXOS_INSTALL_GRUB") == "1":
     if "@canTouchEfiVariables@" == "1":
-        subprocess.check_call(["@gummiboot@/bin/gummiboot", "--path=@efiSysMountPoint@", "install"])
+        subprocess.check_call(["@systemd@/bin/bootctl", "--path=@efiSysMountPoint@", "install"])
     else:
-        subprocess.check_call(["@gummiboot@/bin/gummiboot", "--path=@efiSysMountPoint@", "--no-variables", "install"])
+        subprocess.check_call(["@systemd@/bin/bootctl", "--path=@efiSysMountPoint@", "--no-variables", "install"])
 
 mkdir_p("@efiSysMountPoint@/efi/nixos")
 mkdir_p("@efiSysMountPoint@/loader/entries")

nixos/modules/system/boot/loader/gummiboot/gummiboot.nix

···
 
     isExecutable = true;
 
-    inherit (pkgs) python gummiboot;
+    inherit (pkgs) python;
+
+    systemd = config.systemd.package;
 
     nix = config.nix.package.out;
 
···
 
       type = types.bool;
 
-      description = "Whether to enable the gummiboot UEFI boot manager";
+      description = "Whether to enable the systemd-boot (formerly gummiboot) EFI boot manager";
     };
   };
 

nixos/tests/installer.nix

···
                 pkgs.unionfs-fuse
                 pkgs.ntp
                 pkgs.nixos-artwork
-                pkgs.gummiboot
                 pkgs.perlPackages.XMLLibXML
                 pkgs.perlPackages.ListCompare
               ]