Start making all .cpp files compile-able on all platforms.

src/ports/SkOSLibrary_win.cpp

Index: src/ports/SkOSLibrary_win.cpp
diff --git a/src/ports/SkOSLibrary_win.cpp b/src/ports/SkOSLibrary_win.cpp
index ca80415391b8eacd111bc5f221784cd1bb80725d..69754db375c759979159eab80fc1f4813861a4db 100644
--- a/src/ports/SkOSLibrary_win.cpp
+++ b/src/ports/SkOSLibrary_win.cpp
@@ -5,6 +5,9 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
+#include "SkTypes.h"
+#if defined(SK_BUILD_FOR_WIN32)
+
 #include "SkOSLibrary.h"
 #include <windows.h>
 
@@ -15,3 +18,5 @@ void* DynamicLoadLibrary(const char* libraryName) {
 void* GetProcedureAddress(void* library, const char* functionName) {
     return ::GetProcAddress((HMODULE)library, functionName);
 }
+
+#endif//defined(SK_BUILD_FOR_WIN32)