re PR c++/54764 (In class initialization of non-static lambda member can't be used in class with default template paramer)

	PR c++/54764
	PR c++/55972
	* name-lookup.h (tag_scope): Add ts_lambda.
	* semantics.c (begin_lambda_type): Use it.
	* decl.c (xref_tag_1): Set CLASSTYPE_LAMBDA_EXPR.
	* pt.c (check_default_tmpl_args): Ignore lambdas.
	(push_template_decl_real): Handle lambdas.
	* tree.c (no_linkage_check): Adjust lambda check.

From-SVN: r196742