Fixed all instances of the usage of wcstombs to use a sizeof() of whatever the destination is instead of the source size.

src/WIN/win_language.c

@@ -198,7 +198,7 @@ int file_dlg_w(HWND hwnd, WCHAR *f, WCHAR *fn, int save)
 	}
         if (r)
         {
-		wcstombs(openfilestring, wopenfilestring, 520);
+		wcstombs(openfilestring, wopenfilestring, sizeof(openfilestring));
                 pclog("File dialog return true\n");
                 return 0;
         }