Remove the GN *sdk targets

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") {
+# This is included by reference in the //build/config/compiler:runtime_library
+# config that is applied to all targets. It is here to separate out the logic
+# that is Mac-only. Please see that target for advice on what should go in
+# :runtime_library vs. :compiler.
+config("runtime_library") {
   common_flags = [
     "-isysroot",
     sysroot,
     "-mmacosx-version-min=$mac_deployment_target",
   ]
 
   asmflags = common_flags
   cflags = common_flags
   ldflags = common_flags
 }
@@ skipping 12 matching lines @@
       "-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.
 }