A replacement for mock written in C

Most builds these days are done in chroot's in order to isolate
API/ABI changes between vendor distros.

One common tool is mock (there are several others) that
is used to populate a chroot, mount /proc and other file
system information, run a build, and then undo the changes.

There are other tools similar to mock. The problem with most of the
tools is that they are scripted rather than in C. While the scripting
permits easy adaptation to various "Have it your own way!" conditions,
the divergence also makes it difficult to create a simple and easy to
use tool to build from *.src.rpm's reproducibly. E.g. mock needs a fair
amount of configuration, and is too closely tied to one specific
depsolver, for generally "portable" usage.

The other and deeper issue is that yum+mock expect *exactly*
the same version of rpm running both inside and outside of the
chroot. This implicit requirement on rpm version isn't necessary
(the just build system from bogdano uses the rpm version within
the chroot, permitting different versions to be run inside <-> outside
the chroot).

mock is also encumbered with various caching operations and speedups
that yum and yum alone uses/needs.

So there's a need for a tool that splits the mechanical operations of mount/unmount
and running the build from the depsolver baggage imposed by yum+mock implicit designs.