[Chromecast] Include all stdlibc++/libgcc symbols in cast_shell.

build/config/BUILDCONFIG.gn

 # Copyright (c) 2013 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.
 
 # =============================================================================
 # PLATFORM SELECTION
 # =============================================================================
 #
 # There are two main things to set: "os" and "cpu". The "toolchain" is the name
 # of the GN thing that encodes combinations of these things.
@@ skipping 489 matching lines @@
 # Executable defaults.
 _executable_configs =
     _native_compiler_configs + [ "//build/config:default_libs" ]
 if (is_win) {
   _executable_configs += _windows_linker_configs
 } else if (is_mac) {
   _executable_configs += [
     "//build/config/mac:mac_dynamic_flags",
     "//build/config/mac:mac_executable_flags",
   ]
-} else if (is_linux || is_android) {
+} else if (is_linux || is_android || is_chromecast) {

[brettw, 2015/12/02 18:43:35]

You can't use is_chromecast from here. As described in my following comment,
you're seeing it being implicitly global in your build since you've set it
externally.

If we need a separate config here (I asked a question on this below), we should
refactor this so there's one "//build/config:executable_config" config and that
conditionally references the platform-specific ones based on the various flags.

[bcf, 2015/12/02 23:33:01]

Okay. How does something like PS12 look?

   _executable_configs += [ "//build/config/gcc:executable_ldconfig" ]
   if (is_android) {
     _executable_configs += [ "//build/config/android:executable_config" ]
+  } else if (is_chromecast) {
+    _executable_configs += [ "//build/config/chromecast:executable_config" ]
   }
 }
 set_defaults("executable") {
   configs = _executable_configs
 }
 
 # Static library defaults.
 set_defaults("static_library") {
   configs = _native_compiler_configs
 }
 
 # Shared library and loadable module defaults (also for components in component
 # mode).
 _shared_library_configs =
     _native_compiler_configs + [ "//build/config:default_libs" ]
 if (is_win) {
   _shared_library_configs += _windows_linker_configs
 } else if (is_mac) {
   _shared_library_configs += [ "//build/config/mac:mac_dynamic_flags" ]
 } else if (is_android) {
   # Strip native JNI exports from shared libraries by default. Binaries that
   # want this can remove this config.
   _shared_library_configs +=
       [ "//build/config/android:hide_native_jni_exports" ]
+} else if (is_chromecast) {
+  _shared_library_configs += [ "//build/config/chromecast:shlib_config" ]
 }
 set_defaults("shared_library") {
   configs = _shared_library_configs
 }
 set_defaults("loadable_module") {
   configs = _shared_library_configs
 }
 if (is_component_build) {
   set_defaults("component") {
     configs = _shared_library_configs
@@ skipping 33 matching lines @@
     forward_variables_from(invoker, "*")
 
     # All shared libraries must have the sanitizer deps to properly link in
     # asan mode (this target will be empty in other cases).
     if (!defined(deps)) {
       deps = []
     }
     deps += [ "//build/config/sanitizers:deps" ]
   }
 }