This all started with me wondering why pigz was not used for compressing
generated tarballs with abuild rootbld even though I have it
installed. As it turns out, pigz is (by default) not installed within
the rootbld environment. In order to fix this, I propose a more general
feature where people can specify extra packages that should be
installed, within the environment created by abuild rootbld, via a
configuration option.
Apart from pigz, I also deem this useful for install debugging tools
e.g. strace or stuff like cmd:sha512sum for faster checksum
generation.