* ntdll.h: Reorder NT status flags. Fix a case difference. Add

	* ntdll.h: Reorder NT status flags.  Fix a case difference. Add
	STATUS_CANNOT_DELETE flag.
	* syscalls.cc (unlink_nt): Change initial NtOpenFile to request
	FILE_SHARE_DELETE sharing mode.  Change comment accordingly.
	If setting delete disposition failed with STATUS_CANNOT_DELETE, try
	to delete using delete-on-close.  Explain why.
	Rearrange setting R/O DOS attribute after trying to delete.  Simplify
	comment.