Fix PR16543

Fix PR16543

Tests in gdb.gdb fail because directory gdb/testsuite/gdb.gdb doesn't
exist in build tree.  This patch appends gdb.gdb/Makefile in AC_OUTPUT,
and adds new Makefile.in in gdb.gdb, so that directory gdb.gdb can be
created during configure.

With this patch applied, tests under gdb.gdb can be run,

$ make check RUNTESTFLAGS='--directory=gdb.gdb'

Using /usr/share/dejagnu/baseboards/unix.exp as board description file for target.
Using /usr/share/dejagnu/config/unix.exp as generic interface file for target.
Using ../../../../git/gdb/testsuite/config/unix.exp as tool-and-target-specific interface file.
Running ../../../../git/gdb/testsuite/gdb.gdb/complaints.exp ...
Running ../../../../git/gdb/testsuite/gdb.gdb/observer.exp ...
Running ../../../../git/gdb/testsuite/gdb.gdb/python-interrupts.exp ...
FAIL: gdb.gdb/python-interrupts.exp: signal SIGINT
Running ../../../../git/gdb/testsuite/gdb.gdb/python-selftest.exp ...
FAIL: gdb.gdb/python-selftest.exp: call catch_command_errors(execute_command, "python print 5", 0, RETURN_MASK_ALL)
Running ../../../../git/gdb/testsuite/gdb.gdb/selftest.exp ...
Running ../../../../git/gdb/testsuite/gdb.gdb/xfullpath.exp ...

                === gdb Summary ===

gdb/testsuite:

2014-02-10  Yao Qi  <yao@codesourcery.com>

	PR testsuite/16543
	* configure.ac: Append gdb.gdb/Makefile in AC_OUTPUT.
	* configure: Regenerated.
	* Makefile.in: New file.