* getfacl.c (usage): Add flags description.
	(main): Print suid/sgid/vtx flags if available.
	* utils.xml (getfacl): Document additional suid/sgid/vtx flag printing.
	* sec_acl.cc (setacl): Add comment.  Handle NULL ACE for SUID, SGID,
	and VTX bits.  Create owner, group, other and NULL entries in the same
	way and in the same order as alloc_sd.
	(getacl): Skip NULL ACE.
	* uinfo.cc (pwdgrp::fetch_account_from_windows): Disallow creating an
	entry for "NULL SID".
	* uinfo.cc (cygheap_pwdgrp::init): Fix comment.  Rearrange code for
	style.
	(cygheap_pwdgrp::nss_init_line): Disable db_prefix and db_separator
	settings.  Add comment.
	(pwdgrp::fetch_account_from_windows): Drop outdated comment.  Fix code
	fetching primary group gid of group setting in SAM description field.
	Change comment accordingly.
	* ntsec.xml: Disable description of db_prefix and db_separator settings.
	* setfacl.c (usage): Drop outdated note that default ACEs are not
	taken into account.
	* utils.xml (setfacl): Drop outdated note that default ACEs are not
	taken into account.
	* uinfo.cc (pwdgrp::fetch_account_from_windows): Disallow user accounts
	as groups.  Add comment.
	* ntsec.xml (ntsec-common): Drop outdated comment about underdeveloped
	Solaris ACL API support.