Allow Objective-c++ to recognise lambdas.

Allow Objective-c++ to recognise lambdas.

gcc/cp:

	* parser.c (cp_parser_primary_expression): If parsing an
	objective-c++ message expression fails, see if a lambda is present.
	(cp_parser_objc_message_receiver): Don't assume that, if a message
	receiver expression fails, it is a hard error.

gcc/testsuite:

	* obj-c++.dg/lambda-0.mm New.
	* obj-c++.dg/lambda-1.mm New.
	* obj-c++.dg/syntax-error-6.mm Adjust for revised error messages.

From-SVN: r219125