Set target_arch to ia32 instead of x86_64 on 32bit userland 64bit kernel systems.

build/common.gypi

 # 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.
 
 {
   'variables': {
     # .gyp files should set chromium_code to 1 if they build Chromium-specific
     # code, as opposed to external code.  This variable is used to control
     # such things as the set of warnings to enable, and whether warnings are
     # treated as errors.
@@ skipping 89 matching lines @@
           # Compute the architecture that we're building for. Default to the
           # architecture that we're building on.
           ['OS=="linux" or OS=="freebsd" or OS=="openbsd"', {
             # This handles the Linux platforms we generally deal with. Anything
             # else gets passed through, which probably won't work very well;
             # such hosts should pass an explicit target_arch to gyp.
             #
             # NOTE: currently only nacl is generating gyp files on an arm board.
             #    The arm.* -> arm substitution in chrome's common.gypi isn't
             #    appropriate in that context as we actually use target_arch==arm
-            #    to me x86 -> arm cross compile. When actually running on an arm
-            #    board, we'll generate ia32 for now, so that the generation
+            #    to mean x86 -> arm cross compile. When actually running on an
+            #    arm board, we'll generate ia32 for now, so that the generation
             #    succeeds.
             'target_arch%':
-              '<!(uname -m | sed -e "s/i.86/ia32/;s/x86_64/x64/;s/amd64/x64/;s/arm.*/ia32/")'
+                '<!(echo "<!pymod_do_main(detect_nacl_host_arch)" | sed -e "s/arm.*/ia32/")',
+
           }, {  # OS!="linux"
             'target_arch%': 'ia32',
           }],
         ]
       },
       # These come from the above variable scope.
       'nacl_standalone%': '<(nacl_standalone)',
       'target_arch%': '<(target_arch)',
       'branding%': '<(branding)',
       'buildtype%': '<(buildtype)',
@@ skipping 693 matching lines @@
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
   'includes': [
     'untrusted.gypi',
   ],
 }