ARM64: Enable shorten-64-to-32 warning

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 372 matching lines @@
           '-Wno-long-long',
           '-pthread',
           '-fno-exceptions',
           '-pedantic',
           # Don't warn about the "struct foo f = {0};" initialization pattern.
           '-Wno-missing-field-initializers',
         ],
         'cflags_cc': [ '-Wnon-virtual-dtor', '-fno-rtti', '-std=gnu++0x' ],
         'ldflags': [ '-pthread', ],
         'conditions': [
-          # TODO(arm64): It'd be nice to enable this for arm64 as well,
-          # but the Assembler requires some serious fixing first.
-          [ 'clang==1 and v8_target_arch=="x64"', {
+          [ 'clang==1 and (v8_target_arch=="x64" or v8_target_arch=="arm64")', {
             'cflags': [ '-Wshorten-64-to-32' ],
           }],
           [ 'host_arch=="ppc64" and OS!="aix"', {
             'cflags': [ '-mminimal-toc' ],
           }],
           [ 'visibility=="hidden" and v8_enable_backtrace==0', {
             'cflags': [ '-fvisibility=hidden' ],
           }],
           [ 'component=="shared_library"', {
             'cflags': [ '-fPIC', ],
@@ skipping 230 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'],
       ],
     }],
   ],
 }