Improve call-process-region error message.

* src/callproc.c (Fcall_process_region): Include directory component
in mkstemp error message.

Fixes: debbugs:11586

src/ChangeLog

+2012-05-30  Jim Meyering  <meyering@redhat.com>
+
+	* callproc.c (Fcall_process_region): Include directory component
+	in mkstemp error message (Bug#11586).
+
 2012-05-30  Paul Eggert  <eggert@cs.ucla.edu>
 
 	* alloc.c, lisp.h (make_pure_vector): Now static.

src/callproc.c

@@ -1015,7 +1015,7 @@ usage: (call-process-region START END PROGRAM &optional DELETE BUFFER DISPLAY &r
       UNBLOCK_INPUT;
       if (fd == -1)
 	report_file_error ("Failed to open temporary file",
-			   Fcons (Vtemp_file_name_pattern, Qnil));
+			   Fcons (build_string (tempfile), Qnil));
       else
 	close (fd);
     }