* APKBUILD: Leverage default_prepare and use builddir (no _).
* APKBUILD: Introduce some constants for better DRY-ness,
reformat package() function, create there a workdir
(otherwise buildbot won't start).
* buildslave.initd: Put openrc-run in shebang.
It has not been tested, as buildslave setup is a bit more complicated.
http://docs.buildbot.net/0.8.9/manual/installation.html#creating-a-buildslave