> Perhaps we could associate the line number value with it, though, and
> pass that to the plugin, so that when the plugin parsed its input it would
> have an accurate line number to report when errors were encountered.

Turns out this is already doable -- you can get the line number of the
bracketed text object by using cfg_obj_line(obj). I think it's only necessary
to add a 'lineno' parameter to dns_dyndb_load().

> (If the plugin is parsing its input using libisccfg, then we may need
> to update libisccfg so you can set an initial line number. I can't recall
> whether such a mechanism already exists.)

This mechanism, however, does not yet exist.

I'd implement it as a lexer function, isc_lex_setsourceline(), and call
that on parser->lexer before calling cfg_parse_buffer().