To fix https://bugs.php.net/bug.php?id=77372 and improve support of `<input type="file" name="files" multiple webkitdirectory>` I introduced another item to the `$_FILES` array called `full_path`, containing the full filename, as supplied by the user-agent.
Co-authored-by: Björn Tantau <bjoern@bjoern-tantau.de>