Remove more old cruft.  Remove Windows NT4 and 2000 from comments
	throughout, unless it still makes sense.
	* dlfcn.cc (dlopen): Drop W2K-only code to make loaded DLL persistent.
	* fhandler_floppy.cc (fhandler_dev_floppy::get_drive_info): Drop code
	trying to use information from NtQueryVolumeInformationFile.
	* fhandler_socket.cc (fhandler_socket::close): Drop code snippet
	disabled since 2008.
	* mount.cc (MINIMAL_WIN_NTFS_FLAGS): Add flag values set on all
	NTFS since Windows XP.
	(get_volume_path_names_for_volume_name): Remove.
	(dos_drive_mappings::dos_drive_mappings): Call Win32 function
	GetVolumePathNamesForVolumeNameW directly.
	* path.cc (file_get_fnoi): Drop test for NT4-only return code.
	* sched.cc: Add FIXME to global comment.  Reformat comments throughout.
	* spawn.cc (child_info_spawn::worker): Just call official IsProcessInJob
	function rather than to test undocumented TEB member.
	* winlean.h: Drop Mingw32-related defines.
	* include/limits.h (PTHREAD_KEYS_MAX): Raise value to reflect minimum
	value available on XP and later.

2013-03-13  Corinna Vinschen  <corinna@vinschen.de>
Fix formatting in ChangeLog.64bit