GN: Use x86_64-nacl-gcc with -m32 rather then i686-nacl-gcc

build/toolchain/nacl/BUILD.gn

 # Copyright (c) 2014 The Native Client 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/nacl/config.gni")
 import("//build/toolchain/nacl_toolchain.gni")
 
 # Add the toolchain revision as a preprocessor define so that sources are
 # rebuilt when a toolchain is updated.
@@ skipping 88 matching lines @@
   strip = "finalize"
 }
 
 pnacl_toolchain("newlib_pnacl_nonsfi") {
   executable_extension = ""
   strip = "strip"
 }
 
 template("nacl_glibc_toolchain") {
   toolchain_cpu = target_name
+  toolchain_cc_args = ""
   assert(defined(invoker.toolchain_tuple), "Must define toolchain_tuple")
   assert(defined(invoker.toolchain_package), "Must define toolchain_package")
   assert(defined(invoker.toolchain_revision), "Must define toolchain_revision")
   forward_variables_from(invoker,
                          [
                            "toolchain_package",
                            "toolchain_revision",
+                           "toolchain_cc_args",
                          ])
 
   toolprefix = rebase_path("${nacl_toolchain_dir}/${toolchain_package}/bin/" +
                                invoker.toolchain_tuple + "-",
                            root_build_dir)
 
   # TODO(mcgrathr): Hoist this to top level when
   # https://code.google.com/p/chromium/issues/detail?id=395883 is fixed.
   if (host_os == "win") {
     toolsuffix = ".exe"
   } else {
     toolsuffix = ""
   }
 
   nacl_toolchain("glibc_" + toolchain_cpu) {
     is_clang = false
     is_nacl_glibc = true
 
-    cc = toolprefix + "gcc" + toolsuffix
-    cxx = toolprefix + "g++" + toolsuffix
+    cc = toolprefix + "gcc" + toolsuffix + toolchain_cc_args
+    cxx = toolprefix + "g++" + toolsuffix + toolchain_cc_args
     ar = toolprefix + "ar" + toolsuffix
     ld = cxx
     readelf = toolprefix + "readelf" + toolsuffix
     nm = toolprefix + "nm" + toolsuffix
     strip = toolprefix + "strip" + toolsuffix
   }
 }
 
 nacl_glibc_toolchain("x86") {
   toolchain_package = "nacl_x86_glibc"
   toolchain_revision = nacl_x86_glibc_rev
-  toolchain_tuple = "i686-nacl"
+
+  # i686-nacl-gcc is not in goma (adding it would be tricky) so we use
+  # x86_64-nacl compiler with the -m32 flags.
+  toolchain_tuple = "x86_64-nacl"
+  toolchain_cc_args = " -m32"
 }
 
 nacl_glibc_toolchain("x64") {
   toolchain_package = "nacl_x86_glibc"
   toolchain_revision = nacl_x86_glibc_rev
   toolchain_tuple = "x86_64-nacl"
 }
 
 nacl_glibc_toolchain("arm") {
   toolchain_package = "nacl_arm_glibc"
@@ skipping 102 matching lines @@
   toolchain_tuple = "i686-nacl"
 }
 
 nacl_clang_toolchains("x64") {
   toolchain_tuple = "x86_64-nacl"
 }
 
 nacl_clang_toolchains("arm") {
   toolchain_tuple = "arm-nacl"
 }