mac: Disable fatal linker warnings in arm64 component builds for now.

Bug: 1107955
Change-Id: Ibfa333618be9d1d0296998a5fc53d10a6d59065d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2349923
Commit-Queue: Nico Weber <thakis@chromium.org>
Commit-Queue: Mark Mentovai <mark@chromium.org>
Auto-Submit: Nico Weber <thakis@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#797014}

build/config/compiler/BUILD.gn

@@ -125,8 +125,8 @@ declare_args() {
   # TODO(vitalybuka):
   # 'is_android' breaks content_shell_test_apk on android-kitkat-arm-rel.
   # 'use_xcode_clang' may call old clang.
-  init_stack_vars =
-      !is_android && !use_xcode_clang && (!is_official_build || is_linux || is_chromeos)
+  init_stack_vars = !is_android && !use_xcode_clang &&
+                    (!is_official_build || is_linux || is_chromeos)
 
   # This argument is to control whether enabling text section splitting in the
   # final binary. When enabled, the separated text sections with prefix
@@ -294,7 +294,9 @@ config("compiler") {
     if (fatal_linker_warnings && !is_mac && !is_ios && current_os != "aix") {
       ldflags += [ "-Wl,--fatal-warnings" ]
     }
-    if (fatal_linker_warnings && is_apple) {
+    if (fatal_linker_warnings && is_apple &&
+        # TODO(https://crbug.com/1107955): Enable in arm64 component builds.
+        !(is_mac && target_cpu == "arm64" && is_component_build)) {
       ldflags += [ "-Wl,-fatal_warnings" ]
     }
   } else {
@@ -499,7 +501,8 @@ config("compiler") {
 
   # C11/C++11 compiler flags setup.
   # ---------------------------
-  if (is_linux || is_chromeos || is_android || (is_nacl && is_clang) || current_os == "aix") {
+  if (is_linux || is_chromeos || is_android || (is_nacl && is_clang) ||
+      current_os == "aix") {
     if (target_os == "android") {
       cxx11_override = use_cxx11_on_android
     } else {