[Swan] warningsarefatal

[D. Hugh Redelmeier]

There is a mechanism in the keyword handler for the config-file parser 
controlled by a global variable "warningsarefatal".

It affect whether these diagnostics from keywords.c are warnings or
fatal:

	"%s: %d: keyword %s, invalid value: %s",

	"%s: %d: keyword %s accepts only one value, not %s",

I don't see why it matters much.  Surely "fatal" would be fine and
safer that "warn".

By default, they are warnings.

They are controlled by readwriteconf's -W flag (undocumented) and
addconn's -W flags (documented).

The reason I ask is that the mechanism is implemented in an awkward
way but before I fix that, I'm wondering if deletion is best.

Does anyone use the -W flag?

Does anyone care if the default switches from warning to fatal?