Enable SSE2 compilation for ChromeOS....

build/common.gypi

 # Copyright (c) 2010 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   'variables': {
     # .gyp files or targets should set chromium_code to 1 if they build
@@ skipping 873 matching lines @@
             # compiler optimized the code, since the value is always kept
             # in its specified precision.
             'conditions': [
               ['branding=="Chromium"', {
                 'cflags': [
                   '-march=pentium4',
                   '-msse2',
                   '-mfpmath=sse',
                 ],
               }],
+              # ChromeOS targets Pinetrail, which is ssse3, but most of the
+              # benefit comes from sse2 so this setting allows ChromeOS
+              # to build on other CPUs.  In the future -march=atom would help
+              # but requires a newer compiler.
+              ['chromeos==1', {
+                'cflags': [
+                  '-msse2',
+                ],
+              }],
             ],
             # -mmmx allows mmintrin.h to be used for mmx intrinsics.
             # video playback is mmx and sse2 optimized.
             'cflags': [
               '-m32',
               '-mmmx',
             ],
             'ldflags': [
               '-m32',
             ],
@@ skipping 353 matching lines @@
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }
 
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 # tab-width:2
 # indent-tabs-mode:nil
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