Let gyp_chromium set GYP_CROSSCOMPILE for android and ios.

build/android/envsetup.sh

 #!/bin/bash
 # Copyright (c) 2012 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.
 
 # Sets up environment for building Chromium on Android.
 
 # Make sure we're being sourced (possibly by another script). Check for bash
 # since zsh sets $0 when sourcing.
 if [[ -n "$BASH_VERSION" && "${BASH_SOURCE:-$0}" == "$0" ]]; then
@@ skipping 69 matching lines @@
 # everyone to set use_goma in GYP_DEFINES instead of a GOMA_DIR env var.
 if [[ -d $GOMA_DIR ]]; then
   DEFINES+=" use_goma=1 gomadir=$GOMA_DIR"
 fi
 
 export GYP_DEFINES="${DEFINES}"
 
 # Source a bunch of helper functions
 . ${CHROME_SRC}/build/android/adb_device_functions.sh
 
-# Declare Android are cross compile.
-export GYP_CROSSCOMPILE=1
-
 # Performs a gyp_chromium run to convert gyp->Makefile for android code.
 android_gyp() {
   # This is just a simple wrapper of gyp_chromium, please don't add anything
   # in this function.
-  (
-    "${CHROME_SRC}/build/gyp_chromium" --depth="${CHROME_SRC}" --check "$@"
-  )
+  "${CHROME_SRC}/build/gyp_chromium" --depth="${CHROME_SRC}" --check "$@"
 }