nix: add overlay

ci/variations.nix

@@ -2,6 +2,6 @@
   clangStdenv,
   gccStdenv,
 }: {
-  clang = { buildStdenv = clangStdenv; };
-  gcc = { buildStdenv = gccStdenv; };
+  clang = { stdenv = clangStdenv; };
+  gcc = { stdenv = gccStdenv; };
 }

default.nix

@@ -2,8 +2,8 @@
   lib,
   nix-gitignore,
   pkgs,
+  stdenv,
   keepDebugInfo,
-  buildStdenv ? pkgs.clangStdenv,
 
   pkg-config,
   cmake,
@@ -44,7 +44,7 @@
   withHyprland ? true,
   withI3 ? true,
 }: let
-  unwrapped = buildStdenv.mkDerivation {
+  unwrapped = stdenv.mkDerivation {
     pname = "quickshell${lib.optionalString debug "-debug"}";
     version = "0.2.0";
     src = nix-gitignore.gitignoreSource "/default.nix\n" ./.;

flake.nix

@@ -4,23 +4,28 @@
   };
 
   outputs = { self, nixpkgs }: let
+    overlayPkgs = p: p.appendOverlays [ self.overlays.default ];
+
     forEachSystem = fn:
       nixpkgs.lib.genAttrs
         nixpkgs.lib.platforms.linux
-        (system: fn system nixpkgs.legacyPackages.${system});
+        (system: fn system (overlayPkgs nixpkgs.legacyPackages.${system}));
   in {
-    packages = forEachSystem (system: pkgs: rec {
-      quickshell = pkgs.callPackage ./default.nix {
-        gitRev = self.rev or self.dirtyRev;
-      };
+    overlays.default = import ./overlay.nix {
+      rev = self.rev or self.dirtyRev;
+    };
 
+    packages = forEachSystem (system: pkgs: rec {
+      quickshell = pkgs.quickshell;
       default = quickshell;
     });
 
     devShells = forEachSystem (system: pkgs: rec {
       default = import ./shell.nix {
         inherit pkgs;
-        inherit (self.packages.${system}) quickshell;
+        quickshell = self.packages.${system}.quickshell.override {
+          stdenv = pkgs.clangStdenv;
+        };
       };
     });
   };

overlay.nix

@@ -0,0 +1,5 @@
+{ rev ? null }: (final: prev: {
+  quickshell = final.callPackage ./default.nix {
+    gitRev = rev;
+  };
+})

shell.nix

@@ -1,6 +1,7 @@
 {
   pkgs ? import <nixpkgs> {},
-  quickshell ? pkgs.callPackage ./default.nix {},
+  stdenv ? pkgs.clangStdenv, # faster compiles than gcc
+  quickshell ? pkgs.callPackage ./default.nix { inherit stdenv; },
   ...
 }: let
   tidyfox = import (pkgs.fetchFromGitea {