* errno.cc (errmap): Map ERROR_INVALID_BLOCK_LENGTH to EIO.

* fhandler_raw.cc (fhandler_dev_raw::raw_read): Set more accurate
	errnos instead of EACCES.
	(fhandler_dev_raw::raw_write): Ditto.

winsup/cygwin/errno.cc

@@ -112,6 +112,7 @@ static NO_COPY struct
   X (NOACCESS,			EFAULT),
   X (FILE_INVALID,		ENXIO),
   X (INVALID_ADDRESS,		EOVERFLOW),
+  X (INVALID_BLOCK_LENGTH,	EIO),
   { 0, NULL, 0}
 };