build: tidy nix files

Removes unnesercary nixpkgs overlays and version number.

default.nix

@@ -6,9 +6,7 @@
 }:
 
 stdenv.mkDerivation {
-  pname = "squirrel";
-  version = "0.0.0";
-
+  name = "squirrel";
   src = ./.;
 
   nativeBuildInputs = [ cmake gnumake ];
@@ -31,7 +29,6 @@ stdenv.mkDerivation {
   meta = with lib; {
     homepage = "https://github.com/headblockhead/squirrel";
     description = "Keyboard firmware library inspired by QMK.";
-    licencse = licenses.mit;
     platforms = with platforms; linux;
   };
 }

flake.nix

@@ -3,23 +3,13 @@
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.05";
     flake-utils.url = "github:numtide/flake-utils";
-    xc.url = "github:joerdav/xc";
   };
-  outputs = { self, nixpkgs, flake-utils, ... }@inputs:
+  outputs = { nixpkgs, flake-utils, ... }:
     flake-utils.lib.eachDefaultSystem
       (system:
         let
           pkgs = import nixpkgs {
             inherit system;
-            overlays = [
-              (final: prev: {
-                xc = inputs.xc.packages.x86_64-linux.xc;
-                picotool = pkgs.callPackage ./picotool.nix {
-                  pico-sdk = pkgs.callPackage ./pico-sdk.nix { };
-                };
-                pico-sdk = pkgs.callPackage ./pico-sdk.nix { };
-              })
-            ];
           };
         in
         {
@@ -36,8 +26,9 @@
               cacert
             ];
           };
-          # The firmware (nix build)
+          # The library (nix build)
           packages.squirrel = pkgs.callPackage ./default.nix { };
+          # The tests (nix flake check)
           checks.squirrel-tests = pkgs.callPackage ./tests.nix { };
         }
       );

tests.nix

@@ -7,9 +7,7 @@
 }:
 
 stdenv.mkDerivation {
-  pname = "squirrel-tests";
-  version = "0.0.0";
-
+  name = "squirrel-tests";
   src = ./.;
 
   nativeBuildInputs = [ cmake gnumake gcovr ];
@@ -22,13 +20,13 @@ stdenv.mkDerivation {
   ];
 
   installPhase = ''
-    ctest -T Test -T Coverage --timeout 60 # tests should never take longer than 60 seconds each to complete.
-    cp -r . $out'';
+    mkdir -p $out # Output directory must be created for the build to succeed
+    ctest -T Test -T Coverage --timeout 60
+  '';
 
   meta = with lib; {
     homepage = "https://github.com/headblockhead/squirrel";
     description = "Keyboard firmware library inspired by QMK.";
-    licencse = licenses.mit;
     platforms = with platforms; linux;
   };
 }