* include/sys/file.h: Add extern "C".
	* ntsec.xml (ntsec-mapping): Drop plus-prepended builtin accounts as
	default setting.  Add short explanation in db_prefix: always mode.
	Fix a type.  Drop a paragraph with redundant information.
	* ntsec.xml (ntsec-mapping): Drop plus-prepended builtin accounts as
	default setting.  Add short explanation in db_prefix: always mode.
	Fix a type.  Drop a paragraph with redundant information.
	* passwd.c (usage): Rename DAYS to MINDAYS and MAXDAYS.
	* utils.xml (passwd): Ditto.