Fix compile-command's safe-local-variable condition.

* progmodes/compile.el: Don't treat compile-command as safe if
compilation-read-command might be nil (Bug#4218).

lisp/ChangeLog

+2010-01-09  Chong Yidong  <cyd@stupidchicken.com>
+
+	* progmodes/compile.el: Don't treat compile-command as safe if
+	compilation-read-command might be nil (Bug#4218).
+
 2010-01-09  Jan Djärv  <jan.h.d@swipnet.se>
 
 	* startup.el (command-line-1): Use orig-argi to check for ignored X and

lisp/progmodes/compile.el

@@ -603,7 +603,7 @@ You might also use mode hooks to specify it in certain modes, like this:
 			(file-name-sans-extension buffer-file-name))))))"
   :type 'string
   :group 'compilation)
-;;;###autoload(put 'compile-command 'safe-local-variable 'stringp)
+;;;###autoload(put 'compile-command 'safe-local-variable (lambda (a) (and (stringp a) (or (not (boundp 'compilation-read-command)) compilation-read-command))))
 
 ;;;###autoload
 (defcustom compilation-disable-input nil