diff --git a/src/gn/xcode_object.cc b/src/gn/xcode_object.cc
index de00523..de2975c 100644
--- a/src/gn/xcode_object.cc
+++ b/src/gn/xcode_object.cc
@@ -734,8 +734,6 @@
                        const std::string& source_path,
                        const PBXAttributes& attributes)
     : name_(name), config_name_(config_name), target_for_indexing_(nullptr) {
-  attributes_["BuildIndependentTargetsInParallel"] = "YES";
-
   main_group_.reset(new PBXGroup);
   main_group_->set_autosorted(false);
 
@@ -777,6 +775,8 @@
 void PBXProject::AddAggregateTarget(const std::string& name,
                                     const std::string& shell_script) {
   PBXAttributes attributes;
+  attributes["CLANG_ENABLE_OBJC_WEAK"] = "YES";
+  attributes["CODE_SIGN_IDENTITY"] = "-";
   attributes["CODE_SIGNING_REQUIRED"] = "NO";
   attributes["CONFIGURATION_BUILD_DIR"] = ".";
   attributes["PRODUCT_NAME"] = name;
@@ -788,6 +788,9 @@
 void PBXProject::AddIndexingTarget() {
   DCHECK(!target_for_indexing_);
   PBXAttributes attributes;
+  attributes["CLANG_ENABLE_OBJC_WEAK"] = "YES";
+  attributes["CODE_SIGN_IDENTITY"] = "-";
+  attributes["CODE_SIGNING_REQUIRED"] = "NO";
   attributes["EXECUTABLE_PREFIX"] = "";
   attributes["HEADER_SEARCH_PATHS"] = sources_->path();
   attributes["PRODUCT_NAME"] = "sources";
@@ -829,8 +832,9 @@
                                  : output_basename;
 
   PBXAttributes attributes = extra_attributes;
+  attributes["CLANG_ENABLE_OBJC_WEAK"] = "YES";
+  attributes["CODE_SIGN_IDENTITY"] = "-";
   attributes["CODE_SIGNING_REQUIRED"] = "NO";
-
   attributes["CONFIGURATION_BUILD_DIR"] = output_dir;
   attributes["PRODUCT_NAME"] = product_name;
 
@@ -892,9 +896,10 @@
   PrintProperty(out, rules, "attributes", attributes_);
   PrintProperty(out, rules, "buildConfigurationList", configurations_);
   PrintProperty(out, rules, "compatibilityVersion", "Xcode 3.2");
-  PrintProperty(out, rules, "developmentRegion", "English");
+  PrintProperty(out, rules, "developmentRegion", "en");
   PrintProperty(out, rules, "hasScannedForEncodings", 1u);
-  PrintProperty(out, rules, "knownRegions", std::vector<std::string>({"en"}));
+  PrintProperty(out, rules, "knownRegions",
+                std::vector<std::string>({"en", "Base"}));
   PrintProperty(out, rules, "mainGroup", main_group_);
   PrintProperty(out, rules, "projectDirPath", project_dir_path_);
   PrintProperty(out, rules, "projectRoot", project_root_);
diff --git a/src/gn/xcode_writer.cc b/src/gn/xcode_writer.cc
index 4c3e285..2593514 100644
--- a/src/gn/xcode_writer.cc
+++ b/src/gn/xcode_writer.cc
@@ -368,6 +368,39 @@
       break;
   }
 
+  // Xcode complains that the project needs to be upgraded if those keys are
+  // not set. Since the generated Xcode project is only used for debugging
+  // and the source of truth for build settings is the .gn files themselves,
+  // we can safely set them in the project as they won't be used by "ninja".
+  attributes["CLANG_ANALYZER_LOCALIZABILITY_NONLOCALIZED"] = "YES";
+  attributes["CLANG_WARN__DUPLICATE_METHOD_MATCH"] = "YES";
+  attributes["CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING"] = "YES";
+  attributes["CLANG_WARN_BOOL_CONVERSION"] = "YES";
+  attributes["CLANG_WARN_COMMA"] = "YES";
+  attributes["CLANG_WARN_CONSTANT_CONVERSION"] = "YES";
+  attributes["CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS"] = "YES";
+  attributes["CLANG_WARN_EMPTY_BODY"] = "YES";
+  attributes["CLANG_WARN_ENUM_CONVERSION"] = "YES";
+  attributes["CLANG_WARN_INFINITE_RECURSION"] = "YES";
+  attributes["CLANG_WARN_INT_CONVERSION"] = "YES";
+  attributes["CLANG_WARN_NON_LITERAL_NULL_CONVERSION"] = "YES";
+  attributes["CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF"] = "YES";
+  attributes["CLANG_WARN_OBJC_LITERAL_CONVERSION"] = "YES";
+  attributes["CLANG_WARN_RANGE_LOOP_ANALYSIS"] = "YES";
+  attributes["CLANG_WARN_STRICT_PROTOTYPES"] = "YES";
+  attributes["CLANG_WARN_SUSPICIOUS_MOVE"] = "YES";
+  attributes["CLANG_WARN_UNREACHABLE_CODE"] = "YES";
+  attributes["ENABLE_STRICT_OBJC_MSGSEND"] = "YES";
+  attributes["ENABLE_TESTABILITY"] = "YES";
+  attributes["GCC_NO_COMMON_BLOCKS"] = "YES";
+  attributes["GCC_WARN_64_TO_32_BIT_CONVERSION"] = "YES";
+  attributes["GCC_WARN_ABOUT_RETURN_TYPE"] = "YES";
+  attributes["GCC_WARN_UNDECLARED_SELECTOR"] = "YES";
+  attributes["GCC_WARN_UNINITIALIZED_AUTOS"] = "YES";
+  attributes["GCC_WARN_UNUSED_FUNCTION"] = "YES";
+  attributes["GCC_WARN_UNUSED_VARIABLE"] = "YES";
+  attributes["ONLY_ACTIVE_ARCH"] = "YES";
+
   return attributes;
 }