gcc/cp/
	* pt.c (fn_type_unification): Push tinst level around
	type_unification_real if we aren't explaining.
	* cp-tree.h (TFF_NO_TEMPLATE_BINDINGS): New.
	* error.c (dump_function_decl): Respect it.
	(subst_to_string): Pass it.
libstdc++-v3/
	* testsuite/lib/prune.exp (libstdc++-dg-prune): Also ignore "In
	substitution" lines.

From-SVN: r198161