clang/arm: Push -no-integrated-as into the four targets that need it.

third_party/libvpx_new/libvpx.gyp

 # 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.
 {
   'variables': {
     'libvpx_build_vp9%': 1,
     'libvpx_source%': 'source/libvpx',
     # Disable LTO for neon targets
     # crbug.com/408997
     'use_lto%': 0,
@@ skipping 30 matching lines @@
         'OS_CATEGORY%': 'linux',
       }, {
         'OS_CATEGORY%': '<(OS)',
       }],
     ],
 
     # Location of the intermediate output.
     'shared_generated_dir': '<(SHARED_INTERMEDIATE_DIR)/third_party/libvpx_new',
   },
   'target_defaults': {
+    'conditions': [
+      ['target_arch=="arm" and clang==1', {
+        # TODO(hans) Enable integrated-as (crbug.com/124610).

[Johann, 2015/12/01 15:26:18]

We can generate clang-specific assembly. The issue isn't old-and-crufty vs
new-and-fancy, it's just GAS (gnu assembler syntax) vs clang which are *almost
the same it's so close but not quite*. libvpx assembly is written in UAL which
is for the ARM assembler. It was probably also called ADS at some point because
our scripts are "ads2gas.pl"

In ads2gas.gypi, we use the "clang" scripts (ads2gas_apple.pl because that was
when we first needed it). BUILD.gn doesn't offer to run the apple version of the
script. That script takes a -chromium argument because apple and chromium clang
are *almost the same it's so close but not quite*

[Nico, 2015/12/01 15:32:28]

clang's intentions are to support UAL from what I understand. If it doesn't get
something in UAL right then we can fix clang.

I do intend to work on making the assembly work in both clang and gcc at some
point, but I'd like to first convert most of the build (i.e. this CL).
If there are specific disagreements, please let me know about them :-)

+        'cflags': [
+          '-fno-integrated-as',
+          '-B<(android_toolchain)',  # Else /usr/bin/as gets picked up.
+        ],
+      }],
+    ],
     'target_conditions': [
       ['<(libvpx_build_vp9)==0', {
         'sources/': [ ['exclude', '(^|/)vp9/'], ],
       }],
     ],
     'variables': {
       'conditions': [
         ['OS=="win"', {
           'optimize' :'max',
         }],
@@ skipping 218 matching lines @@
                   '-fstack-protector-all',  # Implies -fstack-protector
                 ],
               },
             }],
           ],
         },
       ],
     }],
   ],
 }