In the PSDK HRESULT_FROM_WIN32() is now an inline function, and it is __HRESULT_FROM_WIN32() which is a macro.
diff --git a/include/winnt.h b/include/winnt.h
index 04f5cf6..71dbf6d 100644
--- a/include/winnt.h
+++ b/include/winnt.h
@@ -398,10 +398,13 @@
/* Misc common WIN32 types */
typedef char CCHAR;
-typedef LONG HRESULT;
typedef DWORD LCID, *PLCID;
typedef WORD LANGID;
typedef DWORD EXECUTION_STATE;
+#ifndef _HRESULT_DEFINED
+#define _HRESULT_DEFINED
+typedef LONG HRESULT;
+#endif
/* Handle type */