* cygerrno.h (__seterrno_from_nt_status): Define. Always set Win32

error code as well as errno. Use throughout where errno is set from
	NT status.
	(set_errno): Evaluate val only once.
	* fhandler_disk_file.cc (fhandler_base::fstat_by_handle): Fix typo in
	debug output.
	* fhandler_mem.cc (fhandler_dev_mem::open): Rely on
	__seterrno_from_nt_status setting Win32 error code in debug output.
	* fhandler_proc.cc (format_proc_uptime): Ditto.
	(format_proc_stat): Ditto.
	* fhandler_process.cc (format_process_stat): Ditto.
	* sysconf.cc (sysconf): Ditto.

winsup/cygwin/fhandler.cc

@@ -665,7 +665,7 @@ fhandler_base::open (int flags, mode_t mode)
 			 create_disposition, create_options, NULL, 0);
   if (!NT_SUCCESS (status))
     {
-      __seterrno_from_win_error (RtlNtStatusToDosError (status));
+      __seterrno_from_nt_status (status);
       if (!nohandle ())
 	goto done;
    }