turn on extended Clang warnings on Windows too

Plus some small rearrangements of the various warning lists.

Change-Id: Ied58f940341d69ddab971a529fd01b1e96b65641
Reviewed-on: https://skia-review.googlesource.com/67720
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>
diff --git a/src/gpu/effects/GrCustomXfermode.cpp b/src/gpu/effects/GrCustomXfermode.cpp
index 98bda3e..bdeda94 100644
--- a/src/gpu/effects/GrCustomXfermode.cpp
+++ b/src/gpu/effects/GrCustomXfermode.cpp
@@ -200,10 +200,14 @@
 ///////////////////////////////////////////////////////////////////////////////
 
 // See the comment above GrXPFactory's definition about this warning suppression.
-#if defined(__GNUC__) || defined(__clang)
+#if defined(__GNUC__)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wnon-virtual-dtor"
 #endif
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wnon-virtual-dtor"
+#endif
 class CustomXPFactory : public GrXPFactory {
 public:
     constexpr CustomXPFactory(SkBlendMode mode)
@@ -228,9 +232,12 @@
 
     typedef GrXPFactory INHERITED;
 };
-#if defined(__GNUC__) || defined(__clang)
+#if defined(__GNUC__)
 #pragma GCC diagnostic pop
 #endif
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#endif
 
 sk_sp<const GrXferProcessor> CustomXPFactory::makeXferProcessor(
         const GrProcessorAnalysisColor&,