libintl updates

[William Orr <will%worrbase.com@localhost>]

Hey,

I've started working on an update to libintl. Currently, I've 
implemented the new functions/macros that were added in GNU gettext that 
take a context argument as described: 
https://www.gnu.org/software/gettext/manual/gettext.html#index-dcpgettext

As far as I can tell from the NEWS shipped with gettext, this covers the 
major API changes.

My plan now is to start working on tests for the lib, and then tackle 
implementing the gettext(1), msgfmt(1) and msgunfmt(1) tools.

Regarding the project page: 
https://wiki.netbsd.org/projects/project/libintl/

- What other extensions were added to the .mo format? I couldn't find 
any major changes in the gettext NEWS or Changelog files.

- Are there any other major API items that I'm missing? Looking at 
gettext.h from GNU gettext, it seems that was it.

Here's the code, in case anyone wants to give me early feedback before I 
submit:
https://gitlab.com/worr/libintl

Thanks,
William Orr