Dump the function def of a macro or call block.

def macro_body(self, node, frame):
        """Dump the function def of a macro or call block."""
        frame = frame.inner()
        frame.symbols.analyze_node(node)
        macro_ref = MacroRef(node)

        explicit_caller = None
        skip_special_params = set()
        args = []
        for idx, arg in enumerate(node.args):
            if arg.name == 'caller':
                explicit_caller = idx
            if arg.name in ('kwargs', 'varargs'):
                skip_special_params.add(arg.name)
            args.append(frame.symbols.ref(arg.name))

        undeclared = find_undeclared(node.body, ('caller', 'kwargs', 'varargs'))

        if 'caller' in undeclared:
            # In older Jinja2 versions there was a bug that allowed caller
            # to retain the special behavior even if it was mentioned in
            # the argument list.  However thankfully this was only really
            # working if it was the last argument.  So we are explicitly
            # checking this now and error out if it is anywhere else in
            # the argument list.
            if explicit_caller is not None:
                try:
                    node.defaults[explicit_caller - len(node.args)]
                except IndexError:
                    self.fail('When defining macros or call blocks the '
                              'special "caller" argument must be omitted '
                              'or be given a default.', node.lineno)
            else:
                args.append(frame.symbols.declare_parameter('caller'))
            macro_ref.accesses_caller = True
        if 'kwargs' in undeclared and not 'kwargs' in skip_special_params:
            args.append(frame.symbols.declare_parameter('kwargs'))
            macro_ref.accesses_kwargs = True
        if 'varargs' in undeclared and not 'varargs' in skip_special_params:
            args.append(frame.symbols.declare_parameter('varargs'))
            macro_ref.accesses_varargs = True

        # macros are delayed, they never require output checks
        frame.require_output_check = False
        frame.symbols.analyze_node(node)
        self.writeline('%s(%s):' % (self.func('macro'), ', '.join(args)), node)
        self.indent()

        self.buffer(frame)
        self.enter_frame(frame)

        self.push_parameter_definitions(frame)
        for idx, arg in enumerate(node.args):
            ref = frame.symbols.ref(arg.name)
            self.writeline('if %s is missing:' % ref)
            self.indent()
            try:
                default = node.defaults[idx - len(node.args)]
            except IndexError:
                self.writeline('%s = undefined(%r, name=%r)' % (
                    ref,
                    'parameter %r was not provided' % arg.name,
                    arg.name))
            else:
                self.writeline('%s = ' % ref)
                self.visit(default, frame)
            self.mark_parameter_stored(ref)
            self.outdent()
        self.pop_parameter_definitions()

        self.blockvisit(node.body, frame)
        self.return_buffer_contents(frame, force_unescaped=True)
        self.leave_frame(frame, with_python_scope=True)
        self.outdent()

        return frame, macro_ref