Really fix OS version detection for Windows 8.1 and later

Fix several problems in d61b52a60e.

See #15321.

Closes https://github.com/wxWidgets/wxWidgets/pull/114

docs/changes.txt

@@ -181,7 +181,7 @@ wxMSW:
 - Correct wxGetOsDescription() for Windows 10 (Tobias Taschner).
 - Make wxListCtrl &c appearance more native on modern systems (Tobias Taschner).
 - Don't send wxActivateEvent for minimized windows (bzcdr).
-- Return correct OS version under Windows 8 and later.
+- Return correct OS version under Windows 8.1 and later.
 
 wxOSX/Cocoa:
 

src/msw/utils.cpp

@@ -1009,13 +1009,16 @@ OSVERSIONINFOEXW wxGetWindowsVersionInfo()
     // RtlGetVersion() directly, if it is available.
 #if wxUSE_DYNLIB_CLASS
     wxDynamicLibrary dllNtDll;
-    if ( dllNtDll.RawLoad(wxS("ntdll.dll")) )
+    if ( dllNtDll.Load(wxS("ntdll.dll"), wxDL_VERBATIM | wxDL_QUIET) )
     {
         typedef LONG /* NTSTATUS */ (WINAPI *RtlGetVersion_t)(OSVERSIONINFOEXW*);
 
         RtlGetVersion_t wxDL_INIT_FUNC(pfn, RtlGetVersion, dllNtDll);
-        if ( pfnRtlGetVersion && pfnRtlGetVersion(&info) )
+        if ( pfnRtlGetVersion &&
+                (pfnRtlGetVersion(&info) == 0 /* STATUS_SUCCESS */) )
+        {
             return info;
+        }
     }
 #endif // wxUSE_DYNLIB_CLASS