[NTG-context] context --autopdf and --showdirectives

[Henning Hraban Ramm]

I’d like to configure the default behaviour of "context --autopdf"; 
since on my Mac I must always write "--autopdf=auto", otherwise context 
tries to call

wine "sumatrapdf.exe" -reuse-instance -bg-color 0xCCCCCC

instead of e.g. "open".

There’s a hint about "directives_pdfview_method", so I wanted to find 
out more about directives:
"context --showdirectives" looks promising;
it tells me "result saved in file: 
.../texmf-context/tex/context/base/mkiv/mtx-context-setters.pdf", but 
that file isn’t there; it is actually in the current directory, but broken.

* How can I configure the command for --autopdf ? (Something in 
texmfcnf.lua?)

* Can we add additional options ("pdfview methods: auto default okular 
pdfxcview sumatra"), e.g. open (should be default on Mac), xdg-open 
(could be default on Linux)...

* What’s wrong with --showdirectives?

Hraban