* posix/regcomp.c (optimize_utf8): Add a note on why we test

* posix/regcomp.c (optimize_utf8): Add a note on why we test

	opr.ctx_type.
	(calc_first): Initialize constraint field.
	(duplicate_node_closure): Use it instead of special casing ANCHORS.
	Use search_duplicated_node to avoid loops.  Fix grammar.
	(duplicate_node): Merge constraint field for all node types.
	(calc_eclosure_iter): Look at constraint field for all node types.
	* posix/regex_internal.c (create_cd_newstate): Don't look at
	create_cd_newstate.

	* posix/tst-rfc3484.c: Add dummy definition of _res_hconf_init.
	* posix/tst-rfc3484-2.c: Likewise.
	* posix/tst-rfc3484-3.c: Likewise.