Make Android-specific LTO disablements have effect only on Android.

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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 2967 matching lines @@
         'defines': ['ENABLE_IPC_FUZZER=1'],
       }],
       ['video_hole==1', {
         'defines': ['VIDEO_HOLE=1'],
       }],
       ['v8_use_external_startup_data==1', {
        'defines': ['V8_USE_EXTERNAL_STARTUP_DATA'],
       }],
       ['use_lto==1 and (target_arch=="ia32" or target_arch=="x64")', {
         # Required for third_party/zlib/crc_folding.c and various other code
-        # that uses SSE.
+        # that uses SSE. TODO(pcc): Remove this once we properly support
+        # subtarget specific code generation in LLVM.
         'ldflags': ['-Wl,-plugin-opt,mcpu=corei7-avx'],
       }],
     ],  # conditions for 'target_defaults'
     'target_conditions': [
       ['<(use_libpci)==1', {
         'defines': ['USE_LIBPCI=1'],
       }],
       ['<(use_openssl)==1', {
         'defines': ['USE_OPENSSL=1'],
       }],
@@ skipping 2888 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # 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',
   },
 }