* test/automated/Makefile.in (GDB): New variable.

(emacs): Use $GDB.

Fixes: debbugs:15991

test/ChangeLog

 2014-06-28  Glenn Morris  <rgm@gnu.org>
 
+	* automated/Makefile.in (GDB): New variable.
+	(emacs): Use $GDB.  (Bug#15991)
+
 	* automated/Makefile.in (WRITE_LOG): New variable.
 	(%.log): Use WRITE_LOG.
 	(test_template): Disable logging.

test/automated/Makefile.in

@@ -47,9 +47,12 @@ EMACSOPT = -batch --no-site-file --no-site-lisp -L "$(SEPCHAR)$(srcdir)"
 # Prevent any settings in the user environment causing problems.
 unexport EMACSDATA EMACSDOC EMACSPATH GREP_OPTIONS
 
+## To run tests under a debugger, set this to eg: "gdb --args".
+GDB =
+
 # The actual Emacs command run in the targets below.
 # Prevent any setting of EMACSLOADPATH in user environment causing problems.
-emacs = EMACSLOADPATH= LC_ALL=C EMACS_TEST_DIRECTORY=$(srcdir) "$(EMACS)" $(EMACSOPT)
+emacs = EMACSLOADPATH= LC_ALL=C EMACS_TEST_DIRECTORY=$(srcdir) $(GDB) "$(EMACS)" $(EMACSOPT)
 
 .PHONY: all check