proced: ppid of process ID 0 can be 0

["Juanma Barranquero" <lekktu@gmail.com>]

proced.el assumes at several places (for example, at
`proced-filter-parents') that you can loop over the ppid, because
you'll eventually find a process with no parent.

That's not true with on Windows, where ppid (0) == 0. That causes a
stack failure, for example, if you hit RET (`proced-refine') over the
PPID of process 0.

I see two ways of fixing this: either removing the assumption from
proced.el, or forcing the Windows implementation of
system_process_attributes to adapt. First is more correct, second is
much easier (see tiny patch below).

Comments?

    Juanma


Index: src/w32.c
===================================================================
RCS file: /cvsroot/emacs/emacs/src/w32.c,v
retrieving revision 1.157
diff -u -2 -r1.157 w32.c
--- src/w32.c	19 Dec 2008 19:50:39 -0000	1.157
+++ src/w32.c	20 Dec 2008 02:34:39 -0000
@@ -3886,7 +3886,8 @@
 		}
 	      attrs = Fcons (Fcons (Qcomm, decoded_cmd), attrs);
-	      attrs = Fcons (Fcons (Qppid,
-				    make_fixnum_or_float (pe.th32ParentProcessID)),
-			     attrs);
+	      if (proc_id != 0)
+		attrs = Fcons (Fcons (Qppid,
+				      make_fixnum_or_float (pe.th32ParentProcessID)),
+			       attrs);
 	      attrs = Fcons (Fcons (Qpri, make_number (pe.pcPriClassBase)),
 			     attrs);