Actually USE the args

native/nanoserver/build.cake

@@ -9,7 +9,7 @@ Task("libSkiaSharp")
 {
     RunCake("../windows/build.cake", "libSkiaSharp", new Dictionary<string, string> {
         { "variant", "nanoserver" },
-        { "gnArgs", "extra_cflags+=[ '-DSK_BUILD_FOR_NANOSERVER' ]" },
+        { "gnArgs", "extra_cflags+=[ '-DSK_BUILD_FOR_NANOSERVER' ] " + ADDITIONAL_GN_ARGS },
         { "arch", "x64" },
     });
 

native/uwp/build.cake

@@ -38,7 +38,8 @@ Task("libSkiaSharp")
             $"extra_cflags=[  " +
             $"  '-DSKIA_C_DLL', '/MD{d}', '/EHsc', '/Z7', " +
             $"  '-DWINAPI_FAMILY=WINAPI_FAMILY_APP', '-DSK_BUILD_FOR_WINRT', '-DSK_HAS_DWRITE_1_H', '-DSK_HAS_DWRITE_2_H', '-DNO_GETENV', '-D_HAS_AUTO_PTR_ETC=1' ] " +
-            $"extra_ldflags=[ '/DEBUG:FULL', '/APPCONTAINER', 'WindowsApp.lib' ]");
+            $"extra_ldflags=[ '/DEBUG:FULL', '/APPCONTAINER', 'WindowsApp.lib' ] " +
+            ADDITIONAL_GN_ARGS);
 
         var outDir = OUTPUT_PATH.Combine(dir);
         EnsureDirectoryExists(outDir);