The function phpbb_clean_path() in functions.php is deprecated and is
replaced by filesystem class. Therefore, this function is moved to the
functions_compatibility file.
PHPBB3-12250
The deprecated passwords functions are no longer used in the core and have
been replaced with the passwords manager. Therefore, the functions are
moved to the functions_compatibility file.
PHPBB3-12239
The needed function phpbb_get_avatar() is defined in
includes/functions_display.php. Include that file in the backwards
compatible function get_user_avatar().
PHPBB3-10018
