Revert of [GN]: BUILD file housecleaning

build/config/mac/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/sysroot.gni")
 import("//build/config/mac/mac_sdk.gni")
 
 config("sdk") {
   common_flags = [
     "-isysroot",
     sysroot,
     "-mmacosx-version-min=$mac_deployment_target",
   ]
 
-  asmflags = common_flags
   cflags = common_flags
   ldflags = common_flags
 }
 
 # On Mac, this is used for everything except static libraries.
 config("mac_dynamic_flags") {
   ldflags = []
 
   if (is_component_build) {
     ldflags += [
       # Path for loading shared libraries for unbundled binaries.
       "-Wl,-rpath,@loader_path/.",
 
       # Path for loading shared libraries for bundled binaries. Get back from
       # Binary.app/Contents/MacOS.
       "-Wl,-rpath,@loader_path/../../..",
     ]
   }
 }
 
 # On Mac, this is used only for executables.
 config("mac_executable_flags") {
   # Remove this when targeting >=10.7 since it is the default in that config.
   ldflags = [ "-Wl,-pie" ]  # Position independent.
 }