buildtools-tarball: brute force remove nativesdk-perl

We don't actually need this, as all the hosts we support have sane host perl,
and by doing this, we avoid the need to install the entire perl standard
library into the buildtools tarball to satisfy various implicit build
dependencies.

Signed-off-by: Christopher Larson <kergoth@gmail.com>
git: don't hardcode the full path to perl

Signed-off-by: Christopher Larson <kergoth@gmail.com>
Merge pull request #150 from kergoth/sb-2649

Fix buildtools-tarball issues breaking our builds