[iOS] Always generate the final binaries using lipo.

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")
 if (is_ios) {
   import("//build/config/ios/ios_sdk.gni")
 }
 import("//build/config/mac/mac_sdk.gni")
 import("//build/config/mac/symbols.gni")
@@ skipping 101 matching lines @@
   ldflags = [ "-Wl,-pie" ]  # Position independent.
 }
 
 # The ldflags referenced below are handled by
 # //build/toolchain/mac/linker_driver.py.
 # Remove this config if a target wishes to change the arguments passed to the
 # strip command during linking. This config by default strips all symbols
 # from a binary, but some targets may wish to specify a saves file to preserve
 # specific symbols.
 config("strip_all") {
-  if (is_ios && additional_toolchains != []) {
-    # For fat build, the generation of the dSYM happens after the fat binary has
-    # been created with "lipo" thus the stripping cannot happen at link time but
-    # after running "lipo" too.
-    _enable_stripping = false
-  } else {
-    _enable_stripping = enable_stripping
-  }
-
-  if (_enable_stripping) {
+  # On iOS, the final applications are assembled using lipo (to support fat
+  # builds). This configuration is thus always empty and the correct flags
+  # are passed to the linker_driver.py script directly during the lipo call.
+  if (enable_stripping && !is_ios) {
     ldflags = [ "-Wcrl,strip,-x,-S" ]
   }
 }