Fix DLGPROC prototype

src/arch/LoadingWindow/LoadingWindow_Win32.cpp

@@ -81,7 +81,7 @@ static HBITMAP LoadWin32Surface( RString sFile, HWND hWnd )
         return ret;
 }
 
-BOOL CALLBACK LoadingWindow_Win32::WndProc( HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam )
+INT_PTR CALLBACK LoadingWindow_Win32::WndProc( HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam )
 {
 	switch( msg )
 	{

src/arch/LoadingWindow/LoadingWindow_Win32.h

@@ -27,7 +27,7 @@ private:
 	RString text[3];
 	HICON m_hIcon;
 
-	static BOOL CALLBACK WndProc( HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam );
+	static INT_PTR CALLBACK WndProc( HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam );
 };
 #define USE_LOADING_WINDOW_WIN32