Bug#800551: nqp: add arm64 support

[Edmund Grimley Evans]

Source: nqp
Version: 2014.07-3

For arm64 it seems to be more a matter of updating the bundled copy of
dyncall than the nqp package itself:

dpkg-source -x nqp_2014.07-3.dsc
cd nqp-2014.07/3rdparty/
rm -r dyncall/
hg clone http://hg.dyncall.org/pub/dyncall/dyncall
cd ..
perl -i -pe 's/armel/arm64 armel/;' debian/control
fakeroot debian/rules binary
# it stops with "error: no previous prototype"
perl -i -pe 's/ -Werror=\S+/ /g;' Makefile
fakeroot debian/rules binary
# "All tests successful."

As you can see, there was a slight problem with warnings being treated
as errors, but I expect it's easy to fix.

This should identify the snapshot of dyncall I was using:

changeset:   29:99eaf237568e
date:        Wed Sep 16 09:55:53 2015 +0200
summary:     Added tag r0.9-RC2 for changeset a461b6977b52