Add a new class gdb.Architecture which exposes GDB's

internal representation of architecture via GDB Python API.

	* Makefile.in: Add entries corresponding to the new file
	python/py-arch.c.
	* NEWS (Python Scripting): Add entries for the new class
	gdb.Architecture and the new method gdb.Frame.architecture.
	* python/py-arch.c: Implement gdb.Architecture class.
	* python/py-frame.c (frapy_arch): Implement the method
	gdb.Frame.architecture().
	(frame_object_methods): Add 'architecture' to the method table.
	* python/python-internal.h: Add declarations of new utility
	functions.
	* python/python.c (_initialize_python): Initialize
	gdb.Architecture class.

	* doc/gdb.texinfo (Architectures In Python): New sub-sub-section
	describing the gdb.Architecture class.
	(Frames In Python): Add description about the new method
	gdb.Frame.architecture().

	* testsuite/gdb.python/frame.exp: Add a test for
	gdb.Frame.architecture() method.

gdb/python/py-frame.c

@@ -167,6 +167,25 @@ frapy_type (PyObject *self, PyObject *args)
   return PyInt_FromLong (type);
 }
 
+/* Implementation of gdb.Frame.architecture (self) -> gdb.Architecture.
+   Returns the frame's architecture as a gdb.Architecture object.  */
+
+static PyObject *
+frapy_arch (PyObject *self, PyObject *args)
+{
+  struct frame_info *frame = NULL;    /* Initialize to appease gcc warning.  */
+  frame_object *obj = (frame_object *) self;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      FRAPY_REQUIRE_VALID (self, frame);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  return gdbarch_to_arch_object (obj->gdbarch);
+}
+
 /* Implementation of gdb.Frame.unwind_stop_reason (self) -> Integer.
    Returns one of the gdb.FRAME_UNWIND_* constants.  */
 
@@ -632,6 +651,9 @@ Return the function name of the frame, or None if it can't be determined." },
   { "type", frapy_type, METH_NOARGS,
     "type () -> Integer.\n\
 Return the type of the frame." },
+  { "architecture", frapy_arch, METH_NOARGS,
+    "architecture () -> gdb.Architecture.\n\
+Return the architecture of the frame." },
   { "unwind_stop_reason", frapy_unwind_stop_reason, METH_NOARGS,
     "unwind_stop_reason () -> Integer.\n\
 Return the reason why it's not possible to find frames older than this." },