Fix nested config in GN.

build/config/win/BUILD.gn

Index: build/config/win/BUILD.gn
diff --git a/build/config/win/BUILD.gn b/build/config/win/BUILD.gn
index b5586952f3162ea040efebda65632bc6205557c7..ba28c5ef78fa6e79fd58f265aba55ae4f945d4d2 100644
--- a/build/config/win/BUILD.gn
+++ b/build/config/win/BUILD.gn
@@ -195,3 +195,13 @@ config("target_winrt") {
     "/EHsc",
   ]
 }
+
+# Internal stuff --------------------------------------------------------------
+
+# Config used by the MIDL template to disable warnings.
+config("midl_warnings") {
+  if (is_clang) {
+    # MIDL generates code like "#endif !_MIDL_USE_GUIDDEF_".
+    cflags = [ "-Wno-extra-tokens" ]
+  }
+}

[Dirk Pranke, 2015/09/11 20:53:01]

What's the advantage to putting this here over leaving it in midl.gni?

[brettw, 2015/09/11 20:58:12]

The old way will make a new config every time you call midl(). This will fail if
you do midl() more than once, and will generate duplicate but identical configs
all over the tree.