Add a [rtc_]build_with_neon variable to unify conditions.

webrtc/build/common.gypi

 # Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 # This file contains common settings for building WebRTC components.
 
@@ skipping 103 matching lines @@
     # Link-Time Optimizations
     # Executes code generation at link-time instead of compile-time
     # https://gcc.gnu.org/wiki/LinkTimeOptimization
     'use_lto%': 0,
 
     # Defer ssl perference to that specified through sslconfig.h instead of
     # choosing openssl or nss directly.  In practice, this can be used to
     # enable schannel on windows.
     'use_legacy_ssl_defaults%': 0,
 
+    # Determines whether NEON code will be built. It might not be selected at

[kjellander_webrtc, 2015/06/18 09:06:23]

I assume you mean "WebRTC doesn't support selecting it at runtime" ? Please
phrase it that way since it's unclear to me in the current comment.

[Andrew MacDonald, 2015/06/25 01:09:09]

No, that's not what I meant :)

Just removed the run-time note to avoid confusion.

+    # run-time.
+    'build_with_neon%': 0,
+
     'conditions': [
       ['build_with_chromium==1', {
         # Exclude pulse audio on Chromium since its prerequisites don't require
         # pulse audio.
         'include_pulse_audio%': 0,
 
         # Exclude internal ADM since Chromium uses its own IO handling.
         'include_internal_audio_device%': 0,
       }, {  # Settings for the standalone (not-in-Chromium) build.
         # TODO(andrew): For now, disable the Chrome plugins, which causes a
@@ skipping 11 matching lines @@
         'include_tests%': 1,
         'restrict_webrtc_logging%': 0,
       }],
       ['OS=="ios"', {
         'build_libjpeg%': 0,
         'enable_protobuf%': 0,
       }],
       ['target_arch=="arm" or target_arch=="arm64"', {
         'prefer_fixed_point%': 1,
       }],
+      ['(target_arch=="arm" and (arm_neon==1 or arm_neon_optional==1)) or target_arch=="arm64"', {
+        'build_with_neon%': 1,

[Andrew MacDonald, 2015/06/17 22:46:21]

gyp wasn't picking up the variable changes in the other scopes, so let's just do
it at one place here. Matches gn better anyway.

+      }],
       ['OS!="ios" and (target_arch!="arm" or arm_version>=7) and target_arch!="mips64el"', {
         'rtc_use_openmax_dl%': 1,
       }, {
         'rtc_use_openmax_dl%': 0,
       }],
     ], # conditions
   },
   'target_defaults': {
     'conditions': [
       ['restrict_webrtc_logging==1', {
@@ skipping 266 matching lines @@
           # of a more specific macro.
           'defines': [
             'WEBRTC_POSIX',
           ],
         }],
       ],
     },
   }, # target_defaults
 }