Fix nix flake and use gcc as compiler

flake.nix

@@ -1,5 +1,5 @@
 {
-  description = "game engine";
+  description = "Project Misth";
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
@@ -10,15 +10,13 @@
     { nixpkgs, ... }:
     let
       system = "x86_64-linux";
-
       pkgs = nixpkgs.legacyPackages.${system};
-      staticPkgs = pkgs.pkgsStatic;
 
-      mruby = staticPkgs.stdenv.mkDerivation {
+      mruby = pkgs.stdenv.mkDerivation {
         pname = "mruby";
         version = "0.0.1";
 
-        src = staticPkgs.lib.cleanSourceWith {
+        src = pkgs.lib.cleanSourceWith {
           src = ./libs;
           name = "mruby-src";
         };
@@ -30,7 +28,6 @@
         nativeBuildInputs = with pkgs; [
           ruby
           gnumake
-          clang
         ];
 
         buildPhase = ''
@@ -49,25 +46,24 @@
         '';
       };
 
-      game-engine = staticPkgs.stdenv.mkDerivation {
-        pname = "game-engine";
+      misth = pkgs.stdenv.mkDerivation {
+        pname = "misth";
         version = "0.1.0";
 
         src = ./.;
 
         nativeBuildInputs = with pkgs; [
-          clang
           pkg-config
           gnumake
           bear
-          ccache
           xxd
+          bash
         ];
 
-        buildInputs = [
-          pkgs.sdl3
-          pkgs.sdl3-ttf
-          pkgs.sdl3-image
+        buildInputs = with pkgs; [
+          sdl3
+          sdl3-ttf
+          sdl3-image
 
           mruby
         ];
@@ -81,43 +77,38 @@
 
         installPhase = ''
           mkdir -p $out/bin
-          cp game-engine $out/bin/game-engine
+          cp bin/misth $out/bin/misth
         '';
-
-        CC = "${pkgs.clang}/bin/clang";
-        CXX = "${pkgs.clang}/bin/clang++";
       };
 
     in
     {
       packages.${system} = {
-        default = game-engine;
-        game-engine = game-engine;
+        default = misth;
+        misth = misth;
         mruby = mruby;
       };
 
       devShells.${system}.default = pkgs.mkShell {
-        inputsFrom = [ game-engine ];
+        inputsFrom = [ misth ];
 
-        packages = [
-          pkgs.clang-tools
-          pkgs.clang
-          pkgs.ccache
-          pkgs.pkg-config
-          pkgs.gnumake
-          pkgs.bear
-          pkgs.ruby
-          pkgs.xxd
+        packages = with pkgs; [
+          clang-tools
+          pkg-config
+          ccache
+          gnumake
+          bear
+          ruby
+          xxd
 
-          pkgs.sdl3
-          pkgs.sdl3-ttf
-          pkgs.sdl3-image
+          sdl3
+          sdl3-ttf
+          sdl3-image
         ];
 
         shellHook = ''
-          export CC=clang
-          export CXX=clang++
-          export LD=clang
+          export CC="ccache gcc"
+          export CXX="ccache g++"
 
           export MRBC=${mruby}/bin/mrbc
           export MRUBY_INCLUDE=${mruby}/include