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

build/config/BUILDCONFIG.gn

Index: build/config/BUILDCONFIG.gn
diff --git a/build/config/BUILDCONFIG.gn b/build/config/BUILDCONFIG.gn
index 3eed120832f10c091058706af881c439adc0454c..3c3b65dba02872148de9c6dd225566634003dec7 100644
--- a/build/config/BUILDCONFIG.gn
+++ b/build/config/BUILDCONFIG.gn
@@ -507,10 +507,12 @@ if (is_win) {
     "//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") {
@@ -535,6 +537,8 @@ if (is_win) {
   # 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