dev-lang/nqp: Convert live ebuild to EAPI7

dev-lang/nqp: Convert live ebuild to EAPI7

Note that this ebuild currently is unusable as:

1. Using moar w/ moar-9999 currently has an odd problem where it needs
   to use a non-existent "ffi.h"

2. Using jvm currently is unsupportable as upstream currently requires
   jdk-1.9/9, which we presently don't have any support for in Gentoo.

Hopefully these issues won't be present when I use this ebuild as a
base for the most recently shipped nqp release.

See also: https://github.com/perl6/nqp/issues/571

Package-Manager: Portage-2.3.66, Repoman-2.3.16
Signed-off-by: Kent Fredric <kentnl@gentoo.org>