Add fs specific errors

include/medialibrary/filesystem/Errors.h

@@ -121,7 +121,7 @@ public:
 #ifndef _WIN32
     System( int err, const std::string& msg )
 #else
-    System( DWORD err, const std::string& msg )
+    System( unsigned long err, const std::string& msg )
 #endif
         : Exception( msg +
                      std::error_code( err, std::generic_category() ).message() )