Basic mac vs linux modes

flake.nix

@@ -3,6 +3,7 @@
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    self.submodules = true;
   };
 
   outputs = { self, nixpkgs }:
@@ -23,11 +24,7 @@
 
             shellHook = ''
               export QMK_HOME="$PWD/qmk_firmware"
-
-              # Symlink tracked keymap into QMK tree
-              if [ -d "$QMK_HOME/keyboards/system76/launch_3" ]; then
-                ln -sfn "$PWD/keymaps/custom" "$QMK_HOME/keyboards/system76/launch_3/keymaps/custom"
-              fi
+              ln -sfn "$PWD/keymaps/custom" "$QMK_HOME/keyboards/system76/launch_3/keymaps/custom"
             '';
           };
         });
@@ -35,20 +32,32 @@
       packages = forAllSystems (system:
         let pkgs = nixpkgs.legacyPackages.${system};
         in {
+          default = self.packages.${system}.firmware;
+
           firmware = pkgs.stdenv.mkDerivation {
             pname = "launch3-firmware";
             version = "0.1.0";
 
             src = ./qmk_firmware;
 
+            postUnpack = ''
+              cp -r ${./keymaps/custom} $sourceRoot/keyboards/system76/launch_3/keymaps/custom
+            '';
+
+            postPatch = ''
+              patchShebangs util/uf2conv.py
+            '';
+
             nativeBuildInputs = [
               pkgs.qmk
               pkgs.python3Packages.appdirs
+              pkgs.python3
             ];
 
             buildPhase = ''
               export HOME=$(mktemp -d)
               export QMK_HOME="$PWD"
+              export SKIP_GIT=true
               qmk compile -kb system76/launch_3 -km custom
             '';