C11 conformance of casinl-like functions.

[mokhi]

> I think you mean acosl, asinl, ...
yeah :D

>  These were implemented quite well in 2012-2013, but not quite finished,
> and not committed.  Only the float and double version were committed.
> The raw versions are still available in
> https://people.freebsd.org/~stephen/catrig*.c.  These have rotted and
> require some editing.  Compare with the committed parts to see most
> of the necessary editing.
Okay, I'll do.
Would you like that I add you on Phabricator for reviewing when my
editing is done?

Thanks and best wishes, Mokhi.