c,c++: use unique_ptr in name_hint to reduce naked 'new'

c,c++: use unique_ptr in name_hint to reduce naked 'new'

gcc/c-family/ChangeLog:
	* name-hint.h (name_hint::name_hint): Use std::unique_ptr for
	param.

gcc/c/ChangeLog:
	* c-decl.cc: Include "make-unique.h".
	(lookup_name_fuzzy): Use ::make_unique rather than "new" when
	making suggest_missing_header and suggest_missing_option.
	* c-parser.cc: Include "make-unique.h"
	(c_parser_error_richloc): Use ::make_unique rather than "new" when
	making suggest_missing_header.

gcc/cp/ChangeLog:
	* name-lookup.cc: Include "make-unique.h".
	(namespace_hints::convert_candidates_to_name_hint): Use
	::make_unique rather than "new" when making
	show_candidate_location and suggest_alternatives.
	(namespace_hints::maybe_decorate_with_limit): Likewise when making
	namespace_limit_reached.
	(suggest_alternatives_for_1): Likewise when making
	suggest_missing_option.
	(maybe_suggest_missing_std_header): Likewise when making
	missing_std_header.
	(macro_use_before_def::maybe_make): Use std::unique_ptr.
	(macro_use_before_def::macro_use_before_def): Make public.
	(lookup_name_fuzzy): Use ::make_unique rather than "new" when
	making suggest_missing_header.
	* parser.cc: Include "make-unique.h".
	(cp_parser_error_1): Use ::make_unique rather than "new" when
	making suggest_missing_header.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>