Address a few TODOs in the gn config

BUILD.gn

 # Copyright 2014 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.
 
 # TODO(jochen): These will need to be user-settable to support standalone V8
 # builds.
 v8_compress_startup_data = "off"
 v8_deprecation_warnings = false
 v8_enable_disassembler = false
 v8_enable_gdbjit = false
@@ skipping 13 matching lines @@
 ###############################################################################
 # Configurations
 #
 config("internal_config") {
   visibility = ":*"  # Only targets in this file can depend on this.
 
   include_dirs = [ "." ]
 
   if (component_mode == "shared_library") {
     defines = [
+      "V8_SHARED",
       "BUILDING_V8_SHARED",
-      "V8_SHARED",
     ]
   }
 }
 
+# This config should only be applied to code using V8 and not any V8 code
+# itself.
+config("external_config") {
+  if (is_component_build) {
+    defines = [
+      "V8_SHARED",
+      "USING_V8_SHARED",
+    ]
+  }
+  include_dirs = [ "include" ]
+}
+
 config("features") {
   visibility = ":*"  # Only targets in this file can depend on this.
 
   defines = []
 
   if (v8_enable_disassembler == true) {
     defines += [
       "ENABLE_DISASSEMBLER",
     ]
   }
@@ skipping 903 matching lines @@
 
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [ "//build/config/compiler:no_chromium_code" ]
   configs += [ ":internal_config", ":features", ":toolchain" ]
 }
 
 ###############################################################################
 # Executables
 #
 
+if (current_toolchain == host_toolchain) {

[Michael Achenbach, 2014/06/05 08:24:35]

nit: no indentation on that level is normal?

+
 executable("mksnapshot") {
   visibility = ":*"  # Only targets in this file can depend on this.
 
   sources = [
     "src/mksnapshot.cc",
   ]
 
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [ "//build/config/compiler:no_chromium_code" ]
   configs += [ ":internal_config", ":features", ":toolchain" ]
 
   deps = [
     ":v8_base",
     ":v8_nosnapshot",
   ]
 
-  libs = []
-
   if (v8_compress_startup_data == "bz2") {
-    libs += [ "bz2" ]
-  }
-
-  if (is_android && current_toolchain != host_toolchain) {
-    libs += [ "log" ]
+    libs = [ "bz2" ]
   }
 }
 
+}
+
 ###############################################################################
 # Public targets
 #
 
 if (component_mode == "shared_library") {
 
 component("v8") {
   sources = [
     "src/v8dll-main.cc",
   ]
 
   if (v8_use_snapshot) {
     deps = [
       ":v8_base",
       ":v8_snapshot",
     ]
   } else {
     deps = [
       ":v8_base",
       ":v8_nosnapshot",
     ]
   }
 
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [ "//build/config/compiler:no_chromium_code" ]
   configs += [ ":internal_config", ":features", ":toolchain" ]
 
-  # TODO(jochen): Support direct dependent configs.
+  direct_dependent_configs = [ ":external_config" ]
+
+  if (is_android && current_toolchain != host_toolchain) {
+    libs += [ "log" ]
+  }
 }
 
 } else {
 
 group("v8") {
   if (v8_use_snapshot) {
     deps = [
       ":v8_base",
       ":v8_snapshot",
     ]
   } else {
     deps = [
       ":v8_base",
       ":v8_nosnapshot",
     ]
   }
-  # TODO(jochen): Support direct dependent configs.
+
+  direct_dependent_configs = [ ":external_config" ]
 }
 
 }