Enable cross compile to android from mac.

build/toolchain/linux/BUILD.gn

 # Copyright 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/toolchain/ccache.gni")
 import("//build/toolchain/clang.gni")
 import("//build/toolchain/gcc_toolchain.gni")
 import("//build/toolchain/goma.gni")
 
 if (use_goma) {
   assert(!use_ccache, "Goma and ccache can't be used together.")
   compiler_prefix = "$goma_dir/gomacc "
 } else if (use_ccache) {
   compiler_prefix = "ccache "
 } else {
   compiler_prefix = ""
 }
 
 gcc_toolchain("arm") {
   cc = "${compiler_prefix}arm-linux-gnueabi-gcc"
   cxx = "${compiler_prefix}arm-linux-gnueabi-g++"
 
   ar = "arm-linux-gnueabi-ar"
   ld = cxx
+  readelf = "arm-linux-gnueabi-readelf"
+  nm = "arm-linux-gnueabi-nm"
 
   toolchain_cpu = "arm"
   toolchain_os = "linux"
   is_clang = false
 }
 
 gcc_toolchain("clang_x86") {
   if (use_clang_type_profiler) {
     prefix = rebase_path("//third_party/llvm-allocated-type/Linux_ia32/bin",
                          root_build_dir)
   } else {
     prefix = rebase_path("//third_party/llvm-build/Release+Asserts/bin",
                          root_build_dir)
   }
   cc = "${compiler_prefix}$prefix/clang"
   cxx = "${compiler_prefix}$prefix/clang++"
-
+  readelf = "readelf"
+  nm = "nm"
   ar = "ar"
   ld = cxx
 
   toolchain_cpu = "x86"
   toolchain_os = "linux"
   is_clang = true
 }
 
 gcc_toolchain("x86") {
   cc = "${compiler_prefix}gcc"
   cxx = "$compiler_prefix}g++"
 
+  readelf = "readelf"
+  nm = "nm"
   ar = "ar"
   ld = cxx
 
   toolchain_cpu = "x86"
   toolchain_os = "linux"
   is_clang = false
 }
 
 gcc_toolchain("clang_x64") {
   if (use_clang_type_profiler) {
     prefix = rebase_path("//third_party/llvm-allocated-type/Linux_x64/bin",
                          root_build_dir)
   } else {
     prefix = rebase_path("//third_party/llvm-build/Release+Asserts/bin",
                          root_build_dir)
   }
   cc = "${compiler_prefix}$prefix/clang"
   cxx = "${compiler_prefix}$prefix/clang++"
 
+  readelf = "readelf"
+  nm = "nm"
   ar = "ar"
   ld = cxx
 
   toolchain_cpu = "x64"
   toolchain_os = "linux"
   is_clang = true
 }
 
 gcc_toolchain("x64") {
   cc = "${compiler_prefix}gcc"
   cxx = "${compiler_prefix}g++"
 
+  readelf = "readelf"
+  nm = "nm"
   ar = "ar"
   ld = cxx
 
   toolchain_cpu = "x64"
   toolchain_os = "linux"
   is_clang = false
 }
 
 gcc_toolchain("mipsel") {
   cc = "mipsel-linux-gnu-gcc"
   cxx = "mipsel-linux-gnu-g++"
   ar = "mipsel-linux-gnu-ar"
   ld = cxx
+  readelf = "mipsel-linux-gnu-readelf"
+  nm = "mipsel-linux-gnu-nm"
 
   toolchain_cpu = "mipsel"
   toolchain_os = "linux"
   is_clang = false
 }