Revert "native opts go nyoom"

This reverts commit e5d187e4c5.

machines/levitation/configuration.nix

@@ -74,8 +74,7 @@
   # Configure nix build
   nix.settings = {
     cores = 8;
-    max-jobs = 6;
+    max-jobs = 8;
-    system-features = [ "gccarch-znver3" ];
   };
 
   # Calibre
@@ -91,37 +90,4 @@
       enableBookUploading = true;
     };
   };
-
-  nixpkgs = {
-    # Native opts go nyoom
-    localSystem = {
-      gcc = {
-        arch = "znver3";
-        tune = "znver3";
-      };
-      system = "x86_64-linux";
-    };
-    # Fix some packages that are broken on nixos-21.11 with march=znver3
-    # We'll substitute these with the version from a second import of nixpkgs without the gcc
-    # configuration.
-    overlays = [
-      (self: super:
-        let
-          vanilla-pkgs = import inputs.nixpkgs-unstable {
-            system = "x86_64-linux";
-            config = {
-              localSystem = {
-                gcc = {
-                  arch = null;
-                  tune = null;
-                };
-              };
-            };
-          };
-        in {
-          libxcrypt = vanilla-pkgs.libxcrypt;
-          perl = vanilla-pkgs.perl;
-        })
-    ];
-  };
 }