* lib/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.
Fix grammar.
(duplicate_node): Merge constraint field for all node types.
(calc_eclosure_iter): Look at constraint field for all node types.
* lib/regex_internal.c (create_cd_newstate): Don't look at
opr.ctx_type.