Name of data-dir is the same as source-dir plus target platform suffix

tools/level_editor/level_editor.vala

@@ -1373,7 +1373,7 @@ namespace Crown
 		provider.load_from_resource("/org/pepper/theme/style.css");
 
 		Project project = new Project();
-		project.load(args[1], args[2], args[3]);
+		project.load(args[1], args[2]);
 
 		var editor = new LevelEditor(project);
 		editor.show_all();

tools/level_editor/project.vala

@@ -34,11 +34,17 @@ namespace Crown
 			_map = new HashMap<string, Guid?>();
 		}
 
-		public void load(string source_dir, string toolchain_dir, string data_dir)
+		public void load(string source_dir, string toolchain_dir)
 		{
 			_source_dir        = File.new_for_path(source_dir);
 			_toolchain_dir     = File.new_for_path(toolchain_dir);
-			_data_dir          = File.new_for_path(data_dir);
+			_data_dir          = File.new_for_path(_source_dir.get_path() +
+#if CROWN_PLATFORM_LINUX
+			"_linux"
+#elif CROWN_PLATFORM_WINDOWS
+			"_windows"
+#endif
+			);
 			_level_editor_test = File.new_for_path(_source_dir.get_path() + "/" + "_level_editor_test.level");
 		}