Enabling /ZW (CompileAsWinRT) option for msvs

test/win/compiler-flags/compile-as-winrt.gyp

Index: test/win/compiler-flags/compile-as-winrt.gyp
diff --git a/test/win/compiler-flags/compile-as-winrt.gyp b/test/win/compiler-flags/compile-as-winrt.gyp
new file mode 100644
index 0000000000000000000000000000000000000000..62a4784415799d78e035c3c2f0f42abe9d184f4a
--- /dev/null
+++ b/test/win/compiler-flags/compile-as-winrt.gyp
@@ -0,0 +1,19 @@
+{

[scottmg, 2016/04/04 22:05:17]

Copyright header.

[munyirik, 2016/04/11 20:07:10]

I'll add it. cl upload for some reason didn't mind this file not having it.

+  'variables': {
+    'msvs_windows_sdk_version': 'v10.0',

[scottmg, 2016/04/04 22:05:17]

Does this need to be a variable and a target value?

[munyirik, 2016/04/11 20:07:10]

The variable isn't required.

+  },
+  'targets': [
+    {
+      'target_name': 'test-compile-as-winrt',
+      'type': 'executable',
+      'msvs_windows_sdk_version': 'v10.0',
+      'msvs_settings': {
+        'VCCLCompilerTool': {
+          'AdditionalUsingDirectories': ['$(VCInstallDir)vcpackages;$(WindowsSdkDir)UnionMetadata;%(AdditionalUsingDirectories)'],
+          'CompileAsWinRT': 'true'
+        }
+      },
+      'sources': ['compile-as-winrt.cc']
+    }
+  ]
+}