* pwdgrp.h (pwdgrp::fetch_account_from_windows): Add bool parameter
	to declaration, set to true by default.
	* uinfo.cc (pwdgrp::fetch_account_from_windows): Add bool parameter
	"ugid_caching".  Only add account to ugid_cache if set to true.
	* grp.cc (gr_ent::enumerate_local): Call fetch_account_from_windows
	with ugid_caching parameter set to false.
	* passwd.cc (pg_ent::enumerate_builtin): Ditto.
	(pg_ent::enumerate_sam): Ditto.
	(pg_ent::enumerate_ad): Ditto.
	* external.cc (cygwin_internal): Add cases for CW_GETNSSSEP,
	CW_GETPWSID and CW_GETGRSID.
	* grp.cc (internal_getgrsid_from_db): New function.
	* passwd.cc (internal_getpwsid_from_db): New function.
	(pg_ent::setent): Add special case for call from mkpasswd/mkgroup.
	* pwdgrp.h (internal_getpwsid_from_db): Declare.
	(internal_getgrsid_from_db): Declare.
	(enum nss_enum_t): Move to include/sys/cygwin.h.
	(class pg_ent): Add comment.
	* uinfo.cc (pwdgrp::fetch_account_from_windows): Fix typo in comment.
	Change "UNIX" to "Unix" in domain name.
	* include/sys/cygwin.h (cygwin_getinfo_types): Add CW_GETNSSSEP,
	CW_GETPWSID and CW_GETGRSID.
	(enum nss_enum_t): Define here.
* fhandler.h (dev_console::is_fullscreen): Delete.
(dev_console::scroll_window): Return bool indicating success.
(dev_console::scroll_screen): New function.
(dev_console::clear_screen): New function.
(fhandler_console::clear_screen): Make __reg3.
(fhandler_console::cursor_set): Ditto.
(fhandler_console::cursor_get): Ditto.
(fhandler_console::cursor_rel): Ditto.
* fhandler_console.cc (dev_console::scroll_buffer): Adapt from
fhandler_console.
(fhandler_console::scroll_buffer): Use dev_console function.
(dev_console::is_fullscreen): Delete.
(dev_console::scroll_window): Return true if we cleared the screen.
Shrink/grow buffer first before scrolling to ensure that there is sufficient
space after scrolling.
(fhandler_console::clear_screen): Make reg3, use dev_console function.
(dev_console::clear_screen): New function adapted from fhandler_console.
(fhandler_console::cursor_set): Make __reg3.
(fhandler_console::cursor_rel): Ditto.
(fhandler_console::cursor_get): Ditto.
(fhandler_console::write): Fix "reverse index".
* dev_console::scroll_buffer): Reinstate clipping region.