Handle up to 63 partitions per drive

Revamp device parsing code.  Introducing support for more partitions
into the shilka-generated parser has the unfortunate side-effect of
raising the size of the DLL by almost 2 Megs.  Therefore we split out
the handling for /dev/sdXY devices into a tiny bit of hand-written
code.

While at it, remove some unused cruft from devices.* and generally
clean up the device class to provide access methods instead of direct
access to members.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

winsup/cygwin/tty.cc

@@ -277,5 +277,5 @@ tty_min::ttyname ()
 {
   device d;
   d.parse (ntty);
-  return d.name;
+  return d.name ();
 }