Only build the x86 arches we actually need.

tools.gyp

 # Copyright (c) 2011 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.
 
 {
   ######################################################################
   'includes': [
     'build/common.gypi',
   ],
   ######################################################################
@@ skipping 16 matching lines @@
   },
   'targets' : [
     {
       'target_name': 'prep_toolchain',
       'type': 'none',
       'dependencies': [
         'untar_toolchains',
         'prep_nacl_sdk',
       ],
       'conditions': [
-        ['target_arch=="ia32" or target_arch=="x64"', {
+        ['target_arch=="ia32" or (target_arch=="x64" and OS=="win")', {
           'dependencies': [
             'crt_init_32',
             'crt_fini_32',
+          ],
+        }],
+        ['(target_arch=="ia32" and OS=="win") or target_arch=="x64"', {
+          'dependencies': [
             'crt_init_64',
             'crt_fini_64',
           ],
         }],
         ['target_arch=="arm"', {
           'dependencies': [
             'crt_init_arm',
             'crt_fini_arm',
           ]
         }],
@@ skipping 187 matching lines @@
                 '--tool', 'pnacl',
                 '--path', '<(pnacl_dir)',
               ],
             },
           ]
         }],
       ]
     },
   ],
   'conditions': [
-    ['target_arch=="ia32" or target_arch=="x64"', {
+    ['(target_arch=="ia32" and OS=="win") or target_arch=="x64"', {
       'targets' : [
         {
           'target_name': 'crt_init_64',
           'type': 'none',
           'dependencies': [
             'untar_toolchains',
             'prep_nacl_sdk'
           ],
           'variables': {
             'nlib_target': 'crti.o',
@@ skipping 31 matching lines @@
               '--no-suffix',
               '--strip=_x86_64'
             ],
           },
           'sources': [
             'src/untrusted/stubs/crtn_x86_64.S'
           ],
         }
       ],
     }],
-    ['target_arch=="ia32" or target_arch=="x64"', {
+    ['target_arch=="ia32" or (target_arch=="x64" and OS=="win")', {
       'targets' : [
         {
           'target_name': 'crt_init_32',
           'type': 'none',
           'dependencies': [
             'untar_toolchains',
             'prep_nacl_sdk'
           ],
           'variables': {
             'nlib_target': 'crti.o',
@@ skipping 83 matching lines @@
             ],
           },
           'sources': [
             'src/untrusted/stubs/crtn_arm.S'
           ],
         }
       ],
     }],
   ],
 }