Update from https://crrev.com/320343

third_party/yasm/yasm.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.
 
 # The yasm build process creates a slew of small C subprograms that
 # dynamically generate files at various point in the build process.  This makes
 # the build integration moderately complex.
 #
 # There are three classes of dynamically generated files:
 #   1) C source files that should be included in the build (eg., lc3bid.c)
@@ skipping 38 matching lines @@
     ],
 
     # Locations for various generated artifacts.
     'shared_generated_dir': '<(SHARED_INTERMEDIATE_DIR)/third_party/yasm',
     'generated_dir': '<(INTERMEDIATE_DIR)/third_party/yasm',
 
     # Various files referenced by multiple targets.
     'version_file': 'version.mac',  # Generated by genversion.
     'genmodule_source': 'genmodule_outfile.c',
   },
+  'target_defaults': {
+    # Silence warnings in libc++ builds (C code doesn't need this flag).
+    'ldflags!': [ '-stdlib=libc++', ],
+  },
   'targets': [
     {
       'target_name': 'yasm',
       'type': 'executable',
       'toolsets': ['host'],
       'dependencies': [
         'config_sources',
         'genmacro',
         'genmodule',
         'genperf',
@@ skipping 499 matching lines @@
       'include_dirs': [
         '<@(yasm_include_dirs)',
 
       ],
       'cflags': [
         '-std=gnu99',
       ],
     },
   ],
 }