Add target_arch check.

ffmpeg.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.
 
 # There's a couple key GYP variables that control how FFmpeg is built:
 #   ffmpeg_branding
 #     Controls whether we build the Chromium or Google Chrome version of
 #     FFmpeg.  The Google Chrome version contains additional codecs.
 #     Typical values are Chromium, Chrome, ChromiumOS, and ChromeOS.
 #   use_system_ffmpeg
@@ skipping 22 matching lines @@
       # when for example it tries to link an ARM symbol on X86.
       'win_debug_Optimization': '2',
       # Run time checks are incompatible with any level of optimizations.
       'win_debug_RuntimeChecks': '0',
     },
   },
   'variables': {
     # Allow overriding the selection of which FFmpeg binaries to copy via an
     # environment variable.  Affects the ffmpeg_binaries target.
     'conditions': [
-      ['armv7 == 1 and arm_neon == 1', {
+      ['target_arch == "arm" and armv7 == 1 and arm_neon == 1', {
         # Need a separate config for arm+neon vs arm
         'ffmpeg_config%': 'arm-neon',
       }, {
         'ffmpeg_config%': '<(target_arch)',
       }],
       ['target_arch == "mipsel"', {
         'asm_sources': [
         ],
       }],
       ['OS == "mac" or OS == "win" or OS == "openbsd"', {
@@ skipping 613 matching lines @@
           '-I', '.',
           # Disable warnings, prevents log spam for things we won't fix.
           '-w',
           '-P', 'config.asm',
         ],
         'yasm_output_path': '<(shared_generated_dir)/yasm'
       },
     },
   ],  # targets
 }