chore: add package build to flake

.gitignore

@@ -1 +1,2 @@
 game/.godot
+result

flake.nix

@@ -33,5 +33,44 @@
           };
         }
       );
+
+      packages = forAllSystems (
+        { pkgs }:
+        {
+          fmm = pkgs.stdenv.mkDerivation {
+            pname = "fmm";
+            version = "0.1.0";
+            src = ./.;
+
+            strictDeps = true;
+
+            nativeBuildInputs = with pkgs; [
+              godot
+            ];
+
+            buildPhase = ''
+              runHook preBuild
+
+              export HOME=$(mktemp -d)
+              mkdir -p $HOME/.local/share/godot/
+              ln -s ${pkgs.godot.export-template}/share/godot/export_templates "$HOME/.local/share/godot/"
+              mkdir -p game/build
+              cd game
+
+              echo "godot --headless --export-debug Linux ./build/fmm"
+              godot --headless --export-release Linux ./build/fmm
+
+              runHook postBuild
+            '';
+            installPhase = ''
+              find .
+              install -D -m 755 -t $out/libexec ./build/fmm
+              install -D -m 644 -t $out/libexec ./build/fmm.pck
+              install -d -m 755 $out/bin
+              ln -s $out/libexec/fmm $out/bin/fmm
+            '';
+          };
+        }
+      );
     };
 }

game/export_presets.cfg

@@ -0,0 +1,41 @@
+[preset.0]
+
+name="Linux"
+platform="Linux"
+runnable=true
+advanced_options=false
+dedicated_server=false
+custom_features=""
+export_filter="all_resources"
+include_filter=""
+exclude_filter=""
+export_path=""
+patches=PackedStringArray()
+encryption_include_filters=""
+encryption_exclude_filters=""
+seed=0
+encrypt_pck=false
+encrypt_directory=false
+script_export_mode=2
+
+[preset.0.options]
+
+custom_template/debug=""
+custom_template/release=""
+debug/export_console_wrapper=1
+binary_format/embed_pck=false
+texture_format/s3tc_bptc=true
+texture_format/etc2_astc=false
+binary_format/architecture="x86_64"
+ssh_remote_deploy/enabled=false
+ssh_remote_deploy/host="user@host_ip"
+ssh_remote_deploy/port="22"
+ssh_remote_deploy/extra_args_ssh=""
+ssh_remote_deploy/extra_args_scp=""
+ssh_remote_deploy/run_script="#!/usr/bin/env bash
+export DISPLAY=:0
+unzip -o -q \"{temp_dir}/{archive_name}\" -d \"{temp_dir}\"
+\"{temp_dir}/{exe_name}\" {cmd_args}"
+ssh_remote_deploy/cleanup_script="#!/usr/bin/env bash
+kill $(pgrep -x -f \"{temp_dir}/{exe_name} {cmd_args}\")
+rm -rf \"{temp_dir}\""