diff --git a/default.nix b/default.nix
index ac42e758ac..15ecb005a5 100644
--- a/default.nix
+++ b/default.nix
@@ -79,207 +79,206 @@ let
   };
 
   # A Nixpkgs overlay.
-  overlay = pkgs: prev:
-    {
-      # ----------- Native Tools -------------
+  overlay = pkgs: prev: {
+    # ----------- Native Tools -------------
 
-      # hfsutils -- Utilities for manipulating HFS volumes & disk images.
-      hfsutils = with pkgs;
-        stdenv.mkDerivation {
-          name = "hfsutils";
-          srcs = ./hfsutils;
+    # hfsutils -- Utilities for manipulating HFS volumes & disk images.
+    hfsutils = with pkgs;
+      stdenv.mkDerivation {
+        name = "hfsutils";
+        srcs = ./hfsutils;
 
-          preConfigure = ''
-            mkdir -p $out/bin
-            mkdir -p $out/lib
-            mkdir -p $out/include
-            mkdir -p $out/share/man/man1
-          '';
-          configureFlags = [ "--mandir=$(out)/share/man" "--enable-devlibs" ];
-        };
+        preConfigure = ''
+          mkdir -p $out/bin
+          mkdir -p $out/lib
+          mkdir -p $out/include
+          mkdir -p $out/share/man/man1
+        '';
+        configureFlags = [ "--mandir=$(out)/share/man" "--enable-devlibs" ];
+      };
 
-      # retro68_tools -- native tools that are part of Retro68
-      retro68_tools = with pkgs;
-        stdenv.mkDerivation {
-          name = "retro68_tools";
-          src = nix-gitignore.gitignoreSource [
-            "/*"
-            "!/CMakeLists.txt"
-            "!/libelf" # should perhaps use nixpkg's libelf instead?
-            "!/cmake"
-            "!/LaunchAPPL"
-            "!/libretro"
-            "!/PEFTools"
-            "!/ResourceFiles"
-            "!/Rez"
-            "!/Elf2Mac"
-            "!/ConvertObj"
-            "!/ConvertDiskImage"
-          ] ./.;
+    # retro68_tools -- native tools that are part of Retro68
+    retro68_tools = with pkgs;
+      stdenv.mkDerivation {
+        name = "retro68_tools";
+        src = nix-gitignore.gitignoreSource [
+          "/*"
+          "!/CMakeLists.txt"
+          "!/libelf" # should perhaps use nixpkg's libelf instead?
+          "!/cmake"
+          "!/LaunchAPPL"
+          "!/libretro"
+          "!/PEFTools"
+          "!/ResourceFiles"
+          "!/Rez"
+          "!/Elf2Mac"
+          "!/ConvertObj"
+          "!/ConvertDiskImage"
+        ] ./.;
 
-          nativeBuildInputs = [ cmake bison flex ];
-          buildInputs = [ boost zlib hfsutils ];
-        };
+        nativeBuildInputs = [ cmake bison flex ];
+        buildInputs = [ boost zlib hfsutils ];
+      };
 
-      # ----------- Binutils & GCC -------------
+    # ----------- Binutils & GCC -------------
 
-      # retro68_binutils -- binutils, without any wrappers
-      retro68_binutils = with pkgs;
-        stdenv.mkDerivation rec {
-          name = "retro68_binutils";
-          src = ./binutils;
+    # retro68_binutils -- binutils, without any wrappers
+    retro68_binutils = with pkgs;
+      stdenv.mkDerivation rec {
+        name = "retro68_binutils";
+        src = ./binutils;
 
-          configureFlags =
-            [ "--target=${stdenv.targetPlatform.config}" "--disable-doc" ]
-            ++ stdenv.targetPlatform.retro68BinutilsConfig or [ ];
-          enableParallelBuilding = true;
+        configureFlags =
+          [ "--target=${stdenv.targetPlatform.config}" "--disable-doc" ]
+          ++ stdenv.targetPlatform.retro68BinutilsConfig or [ ];
+        enableParallelBuilding = true;
 
-          postInstall = let
-            ld = "$out/bin/${stdenv.targetPlatform.config}-ld";
-            ld_real = "$out/bin/${stdenv.targetPlatform.config}-ld.real";
+        postInstall = let
+          ld = "$out/bin/${stdenv.targetPlatform.config}-ld";
+          ld_real = "$out/bin/${stdenv.targetPlatform.config}-ld.real";
 
-          in ''
-            mv ${ld} ${ld_real}
+        in ''
+          mv ${ld} ${ld_real}
 
-            echo "#!${stdenv.shell}" > ${ld}
-            echo "exec \$'' + ''
-              {RETRO68_LD_WRAPPER_${stdenv.targetPlatform.cmakeSystemName}-${ld_real}} \"\$@\"" >> ${ld}
-                              chmod +x ${ld}
+          echo "#!${stdenv.shell}" > ${ld}
+          echo "exec \$'' + ''
+            {RETRO68_LD_WRAPPER_${stdenv.targetPlatform.cmakeSystemName}-${ld_real}} \"\$@\"" >> ${ld}
+                            chmod +x ${ld}
 
-                              rm $out/${stdenv.targetPlatform.config}/bin/ld
-                              ln -s ${ld} $out/${stdenv.targetPlatform.config}/bin/ld
-                            '';
-        };
+                            rm $out/${stdenv.targetPlatform.config}/bin/ld
+                            ln -s ${ld} $out/${stdenv.targetPlatform.config}/bin/ld
+                          '';
+      };
 
-      # retro68_gcc -- gcc, without any wrappers
-      retro68_gcc = with pkgs;
-        stdenv.mkDerivation rec {
-          name = "retro68_gcc";
-          src = ./gcc;
-          buildInputs = [ retro68_binutils gmp mpfr libmpc ];
-          configureFlags = [
-            "--target=${stdenv.targetPlatform.config}"
-            "--enable-languages=c,c++"
-            "--disable-libssp"
-            "MAKEINFO=missing"
-          ] ++ stdenv.targetPlatform.retro68GccConfig or [ ];
-          hardeningDisable = [ "format" ];
-          enableParallelBuilding = true;
+    # retro68_gcc -- gcc, without any wrappers
+    retro68_gcc = with pkgs;
+      stdenv.mkDerivation rec {
+        name = "retro68_gcc";
+        src = ./gcc;
+        buildInputs = [ retro68_binutils gmp mpfr libmpc ];
+        configureFlags = [
+          "--target=${stdenv.targetPlatform.config}"
+          "--enable-languages=c,c++"
+          "--disable-libssp"
+          "MAKEINFO=missing"
+        ] ++ stdenv.targetPlatform.retro68GccConfig or [ ];
+        hardeningDisable = [ "format" ];
+        enableParallelBuilding = true;
 
-          # nix does in-source builds by default, and something breaks
-          buildCommand = ''
-            mkdir -p $out/${stdenv.targetPlatform.config}/bin
-            ln -s ${retro68_binutils}/${stdenv.targetPlatform.config}/bin/* $out/${stdenv.targetPlatform.config}/bin/
+        # nix does in-source builds by default, and something breaks
+        buildCommand = ''
+          mkdir -p $out/${stdenv.targetPlatform.config}/bin
+          ln -s ${retro68_binutils}/${stdenv.targetPlatform.config}/bin/* $out/${stdenv.targetPlatform.config}/bin/
 
-            export target_configargs="--disable-nls --enable-libstdcxx-dual-abi=no --disable-libstdcxx-verbose"
-            $src/configure ${builtins.toString configureFlags} --prefix=$out
-            make -j$NIX_BUILD_CORES
-            make install
-          '';
-        };
+          export target_configargs="--disable-nls --enable-libstdcxx-dual-abi=no --disable-libstdcxx-verbose"
+          $src/configure ${builtins.toString configureFlags} --prefix=$out
+          make -j$NIX_BUILD_CORES
+          make install
+        '';
+      };
 
-      # ----------- Binutils & GCC wrapped for nixpkgs -------------
+    # ----------- Binutils & GCC wrapped for nixpkgs -------------
 
-      # binutils -- binutils with the wrappers provided by nixpkgs 
-      binutils = if pkgs.stdenv.targetPlatform ? retro68 then
-        pkgs.wrapBintoolsWith { bintools = pkgs.retro68_binutils; }
-      else
-        prev.binutils;
+    # binutils -- binutils with the wrappers provided by nixpkgs 
+    binutils = if pkgs.stdenv.targetPlatform ? retro68 then
+      pkgs.wrapBintoolsWith { bintools = pkgs.retro68_binutils; }
+    else
+      prev.binutils;
 
-      # gcc -- gcc with the wrappers provided by nixpkgs
-      gcc = if pkgs.stdenv.targetPlatform ? retro68 then
-        pkgs.wrapCCWith {
-          cc = pkgs.retro68_gcc;
+    # gcc -- gcc with the wrappers provided by nixpkgs
+    gcc = if pkgs.stdenv.targetPlatform ? retro68 then
+      pkgs.wrapCCWith {
+        cc = pkgs.retro68_gcc;
 
-          # don't allow nix to add options for hardening
-          extraBuildCommands = ''
-            echo "" > $out/nix-support/add-hardening.sh
-          '';
+        # don't allow nix to add options for hardening
+        extraBuildCommands = ''
+          echo "" > $out/nix-support/add-hardening.sh
+        '';
 
-          extraPackages = with pkgs.targetPackages; [
-            multiversal
-            import-libraries
-            libretro
-            retro68_setup_hook
-          ];
-        }
-      else
-        prev.gcc;
+        extraPackages = with pkgs.targetPackages; [
+          multiversal
+          import-libraries
+          libretro
+          retro68_setup_hook
+        ];
+      }
+    else
+      prev.gcc;
 
-      # no separate libc package for now
-      libcCrossChooser = name:
-        if name == "retro68" then null else prev.libcCrossChooser name;
+    # no separate libc package for now
+    libcCrossChooser = name:
+      if name == "retro68" then null else prev.libcCrossChooser name;
 
-      retro68_setup_hook = let
-        systemName = pkgs.targetPlatform.cmakeSystemName;
-        toolchain = pkgs.writeTextFile {
-          name = "retro68-cmake-toolchain";
-          text = ''
-            set(CMAKE_SYSTEM_NAME ${systemName})
-            set(CMAKE_SYSTEM_VERSION 1)
-            set(CMAKE_CROSSCOMPILING TRUE)
+    retro68_setup_hook = let
+      systemName = pkgs.targetPlatform.cmakeSystemName;
+      toolchain = pkgs.writeTextFile {
+        name = "retro68-cmake-toolchain";
+        text = ''
+          set(CMAKE_SYSTEM_NAME ${systemName})
+          set(CMAKE_SYSTEM_VERSION 1)
+          set(CMAKE_CROSSCOMPILING TRUE)
 
-            set( REZ "${pkgs.buildPackages.retro68_tools}/bin/Rez" )
-            set(REZ_TEMPLATES_PATH ${pkgs.libretro}/RIncludes)
+          set( REZ "${pkgs.buildPackages.retro68_tools}/bin/Rez" )
+          set(REZ_TEMPLATES_PATH ${pkgs.libretro}/RIncludes)
 
-            include(${./cmake/add_application.cmake})
-          '';
-        };
-        hook = pkgs.writeTextFile {
-          name = "retro68_setup_hook";
-          text = ''
-            export CMAKE_TOOLCHAIN_FILE=${toolchain}
+          include(${./cmake/add_application.cmake})
+        '';
+      };
+      hook = pkgs.writeTextFile {
+        name = "retro68_setup_hook";
+        text = ''
+          export CMAKE_TOOLCHAIN_FILE=${toolchain}
 
-            retro68_addRIncludes() {
-              case $depHostOffset in
-                  -1) local role='BUILD_' ;;
-                  0)  local role="" ;;
-                  1)  local role='TARGET_' ;;
-                  *)  echo "retro68_addRIncludes: Error: Cannot be used with $depHostOffset-offset deps" >2;
-                      return 1 ;;
-              esac
+          retro68_addRIncludes() {
+            case $depHostOffset in
+                -1) local role='BUILD_' ;;
+                0)  local role="" ;;
+                1)  local role='TARGET_' ;;
+                *)  echo "retro68_addRIncludes: Error: Cannot be used with $depHostOffset-offset deps" >2;
+                    return 1 ;;
+            esac
 
-              if [[ -d "$1/RIncludes" ]]; then
-                  export REZ_INCLUDE_PATH+=":$1/RIncludes"
-              fi
-            }
+            if [[ -d "$1/RIncludes" ]]; then
+                export REZ_INCLUDE_PATH+=":$1/RIncludes"
+            fi
+          }
 
-            addEnvHooks "$targetOffset" retro68_addRIncludes
+          addEnvHooks "$targetOffset" retro68_addRIncludes
 
-          '' + (pkgs.lib.optionalString (systemName == "Retro68") ''
-            export RETRO68_LD_WRAPPER_Retro68="${pkgs.buildPackages.retro68_tools}/bin/Elf2Mac"
-            export RETRO68_REAL_LD="${pkgs.buildPackages.retro68_binutils}/bin/m68k-apple-macos-ld.real"
-          '');
-        };
-      in pkgs.makeSetupHook { } hook;
+        '' + (pkgs.lib.optionalString (systemName == "Retro68") ''
+          export RETRO68_LD_WRAPPER_Retro68="${pkgs.buildPackages.retro68_tools}/bin/Elf2Mac"
+          export RETRO68_REAL_LD="${pkgs.buildPackages.retro68_binutils}/bin/m68k-apple-macos-ld.real"
+        '');
+      };
+    in pkgs.makeSetupHook { } hook;
 
-      # ----------- Retro68 core libraries -------------
+    # ----------- Retro68 core libraries -------------
 
-      # multiversal -- multiversal interfaces
-      multiversal = with pkgs;
-        (stdenv.override {
-          cc = stdenv.cc.override { extraPackages = [ ]; };
-        }).mkDerivation {
-          name = "multiversal";
-          src = ./multiversal;
-          nativeBuildInputs = [ buildPackages.ruby ];
-          buildCommand = ''
-            echo $src
-            build=`pwd`
-            (cd $src && ruby make-multiverse.rb -G CIncludes -o "$build")
-            mkdir $out
-            cp -r CIncludes $out/include
-            cp -r RIncludes $out/
-          '' + (if stdenv.targetPlatform.system == "m68k-macos" then ''
-            cp -r lib68k $out/lib
-          '' else ''
-          '');
-          meta = { platforms = [ "m68k-macos" ]; };
-        };
+    # multiversal -- multiversal interfaces
+    multiversal = with pkgs;
+      (stdenv.override {
+        cc = stdenv.cc.override { extraPackages = [ ]; };
+      }).mkDerivation {
+        name = "multiversal";
+        src = ./multiversal;
+        nativeBuildInputs = [ buildPackages.ruby ];
+        buildCommand = ''
+          echo $src
+          build=`pwd`
+          (cd $src && ruby make-multiverse.rb -G CIncludes -o "$build")
+          mkdir $out
+          cp -r CIncludes $out/include
+          cp -r RIncludes $out/
+        '' + (if stdenv.targetPlatform.system == "m68k-macos" then ''
+          cp -r lib68k $out/lib
+        '' else
+          "");
+        meta = { platforms = [ "m68k-macos" ]; };
+      };
 
-      import-libraries = with pkgs;
-        if stdenvNoCC.targetPlatform != retroSystems.m68k
-        then stdenvNoCC.mkDerivation {
+    import-libraries = with pkgs;
+      if stdenvNoCC.targetPlatform != retroSystems.m68k then
+        stdenvNoCC.mkDerivation {
           name = "import-libraries";
           src = ./ImportLibraries;
           buildCommand = ''
@@ -287,41 +286,42 @@ let
             cp $src/*.a $out/lib/
           '';
         }
-        else null;
+      else
+        null;
 
-      libretro = with pkgs;
-        let
-          systemName = pkgs.targetPlatform.cmakeSystemName;
-          toolchain = pkgs.writeTextFile {
-            name = "retro68-cmake-toolchain-bootstrap";
-            text = ''
-              set(CMAKE_SYSTEM_NAME ${systemName})
-              set(CMAKE_SYSTEM_VERSION 1)
-              set(CMAKE_CROSSCOMPILING TRUE)
-            '';
-          };
-        in (pkgs.stdenv.override {
-          cc = stdenv.cc.override { extraPackages = [ ]; };
-        }).mkDerivation {
-          name = "libretro";
-          src = ./libretro;
-
-          nativeBuildInputs = [ buildPackages.cmake ];
-          buildInputs = [ multiversal ];
-
-          buildCommand = ''
-            echo "Build command."
-            cmake $src \
-                    -DCMAKE_INSTALL_PREFIX=$out \
-                    -DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY \
-                    -DCMAKE_BUILD_TYPE=Release \
-                    -DCMAKE_TOOLCHAIN_FILE=${toolchain}
-            cmake --build .
-            cmake --build . --target install
+    libretro = with pkgs;
+      let
+        systemName = pkgs.targetPlatform.cmakeSystemName;
+        toolchain = pkgs.writeTextFile {
+          name = "retro68-cmake-toolchain-bootstrap";
+          text = ''
+            set(CMAKE_SYSTEM_NAME ${systemName})
+            set(CMAKE_SYSTEM_VERSION 1)
+            set(CMAKE_CROSSCOMPILING TRUE)
           '';
-          meta = { platforms = [ "m68k-macos" ]; };
         };
-    };
+      in (pkgs.stdenv.override {
+        cc = stdenv.cc.override { extraPackages = [ ]; };
+      }).mkDerivation {
+        name = "libretro";
+        src = ./libretro;
+
+        nativeBuildInputs = [ buildPackages.cmake ];
+        buildInputs = [ multiversal ];
+
+        buildCommand = ''
+          echo "Build command."
+          cmake $src \
+                  -DCMAKE_INSTALL_PREFIX=$out \
+                  -DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY \
+                  -DCMAKE_BUILD_TYPE=Release \
+                  -DCMAKE_TOOLCHAIN_FILE=${toolchain}
+          cmake --build .
+          cmake --build . --target install
+        '';
+        meta = { platforms = [ "m68k-macos" ]; };
+      };
+  };
 
   pkgs = import <nixpkgs> {
     inherit system;
@@ -342,4 +342,4 @@ let
         [ pkgs.hfsutils pkgs.retro68_tools pkgs.cmake pkgs.gnumake ];
     } // cross) crossPkgs;
 
-  in shell.m68k // shell // { inherit overlay; }
+in shell.m68k // shell // { inherit overlay; }