headers: provide the WinMain prototype to winstore apps

A proper UWP app should create a IFrameworkViewSource class, instantiate it and
call CoreApplication:Run() with it.
https://docs.microsoft.com/en-us/uwp/api/windows.applicationmodel.core

To create the instance the app still needs an entry point and that's still
WinMain:
https://stackoverflow.com/a/42211357/1266123
https://stackoverflow.com/a/53661306/1266123

So we provide the proper prototype for UWP apps as well.
This is still what the C runtime will call.

Signed-off-by: Liu Hao <lh_mouse@126.com>
diff --git a/mingw-w64-headers/include/winbase.h b/mingw-w64-headers/include/winbase.h
index 78b5774..0dc0782 100644
--- a/mingw-w64-headers/include/winbase.h
+++ b/mingw-w64-headers/include/winbase.h
@@ -1093,10 +1093,10 @@
 #if WINAPI_FAMILY_PARTITION (WINAPI_PARTITION_APP)
   WINBASEAPI HLOCAL WINAPI LocalAlloc (UINT uFlags, SIZE_T uBytes);
   WINBASEAPI HLOCAL WINAPI LocalFree (HLOCAL hMem);
-#endif
-#if WINAPI_FAMILY_PARTITION (WINAPI_PARTITION_DESKTOP)
   int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd);
   int WINAPI wWinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, LPWSTR lpCmdLine, int nShowCmd);
+#endif
+#if WINAPI_FAMILY_PARTITION (WINAPI_PARTITION_DESKTOP)
   WINBASEAPI UINT WINAPI GlobalFlags (HGLOBAL hMem);
   WINBASEAPI HGLOBAL WINAPI GlobalHandle (LPCVOID pMem);
   WINBASEAPI SIZE_T WINAPI GlobalCompact (DWORD dwMinFree);