PKGBUILD for lua-systemd. Generated with https://gist.github.com/daurnimator/11148106 then hand edited.

PKGBUILD

pkgname='lua-systemd'
pkgver='scm_0'
pkgrel='0'
pkgdesc='Lua bindings to systemd'
arch=('any')
url='https://github.com/daurnimator/lua-systemd'
license=('MIT')
depends=('luarocks' 'lua')
source=('systemd-scm-0.rockspec' 'git://github.com/daurnimator/lua-systemd')
md5sums=('SKIP' 'SKIP')
install='rock.install'
build() {
    cd 'lua-systemd';
    luarocks make --pack-binary-rock "${srcdir}"/'systemd-scm-0.rockspec';
}
package() {
    cd 'lua-systemd';
    luarocks --to="${pkgdir}/usr" install --deps-mode=none --keep 'systemd-scm-0'.*.rock
    rm -- "${pkgdir}/usr/lib/luarocks/rocks-5.2/manifest"
    install -Dm644 "LICENSE" "${pkgdir}/usr/share/licenses/$pkgname/LICENSE"
}

rock.install

post_install() {
        luarocks-admin make_manifest --local-tree
}
post_remove() {
        luarocks-admin make_manifest --local-tree
}