Fix bug in dwarf-mode.el

I noticed that, occasionally, dwarf-mode would think that the objdump
subprocess was still running after it had clearly exited.  I managed
to reliably reproduce this today and learned that a process sentinel
is not guaranteed to be run with the current buffer set to the process
buffer.  This patch fixes the problem.

I've bumped the version number of dwarf-mode.el to make it easier to
install for users who already have an earlier one installed.

I'm checking this in.

2022-03-15  Tom Tromey  <tromey@adacore.com>

	* dwarf-mode.el: Now 1.7.
	(dwarf--sentinel): Switch to the process buffer.

binutils/ChangeLog

@@ -1,3 +1,8 @@
+2022-03-15  Tom Tromey  <tromey@adacore.com>
+
+	* dwarf-mode.el: Now 1.7.
+	(dwarf--sentinel): Switch to the process buffer.
+
 2022-03-11  Vladimir Mezentsev  <vladimir.mezentsev@oracle.com>
 
 	* MAINTAINERS: Add gprofng maintainer.

binutils/dwarf-mode.el

@@ -1,6 +1,6 @@
 ;;; dwarf-mode.el --- Browser for DWARF information. -*-lexical-binding:t-*-
 
-;; Version: 1.6
+;; Version: 1.7
 
 ;; Copyright (C) 2012-2022 Free Software Foundation, Inc.
 
@@ -62,9 +62,11 @@
           (set-marker (process-mark proc) (point))
 	  (set-buffer-modified-p nil))))))
 
-(defun dwarf--sentinel (_proc _status)
-  (setq mode-line-process nil)
-  (setq dwarf--process nil))
+(defun dwarf--sentinel (proc _status)
+  (when (buffer-live-p (process-buffer proc))
+    (with-current-buffer (process-buffer proc)
+      (setq mode-line-process nil)
+      (setq dwarf--process nil))))
 
 (defun dwarf--invoke (start end &rest command)
   "Invoke a command and arrange to insert output into the current buffer."