Introduce a new gyp flag to warn about to be deprecated APIs

build/standalone.gypi

 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 25 matching lines @@
     'clang_dir%': 'third_party/llvm-build/Release+Asserts',
     'clang_xcode%': 0,
     # Track where uninitialized memory originates from. From fastest to
     # slowest: 0 - no tracking, 1 - track only the initial allocation site, 2
     # - track the chain of stores leading from allocation site to use site.
     'msan_track_origins%': 1,
     'visibility%': 'hidden',
     'v8_enable_backtrace%': 0,
     'v8_enable_i18n_support%': 1,
     'v8_deprecation_warnings': 1,
+    # TODO(jochen): Turn this on.
+    'v8_imminent_deprecation_warnings': 0,
     'msvs_multi_core_compile%': '1',
     'mac_deployment_target%': '10.5',
     'release_extra_cflags%': '',
     'variables': {
       'variables': {
         'variables': {
           'conditions': [
             ['OS=="linux" or OS=="freebsd" or OS=="openbsd" or \
                OS=="netbsd" or OS=="mac" or OS=="qnx" or OS=="aix"', {
               # This handles the Unix platforms we generally deal with.
@@ skipping 581 matching lines @@
     ['use_goma==1 and ("<(GENERATOR)"=="ninja" or clang==1)', {
       'make_global_settings': [
        ['CC_wrapper', '<(gomadir)/gomacc'],
        ['CXX_wrapper', '<(gomadir)/gomacc'],
        ['CC.host_wrapper', '<(gomadir)/gomacc'],
        ['CXX.host_wrapper', '<(gomadir)/gomacc'],
       ],
     }],
   ],
 }