non-root package-building sandbox?

["Ian D. Leroux" <idleroux%fastmail.fm@localhost>]

Is there a tool that would let one build (or better yet test) pkgsrc
packages without installing them to /usr/pkg and without requiring root
privileges?

I've been using pkg_comp for a number of years to keep my /usr/pkg
up-to-date.  It lets me make sure that all packages build successfully
*before* I start messing with my working system (in fact, /usr is
generally mounted read-only; I remount read-write once I have all the
binary packages ready to go and just pkg_chk -ua to update everything
at once).  Unfortunately, as far as I've understood, everything inside
the pkg_comp sandbox must be done as root.  This is slightly
uncomfortable when I'm just building things, but when something goes
wrong and I want to debug (or when doing development on a package) it
becomes annoying: my root account is not set up as a comfortable
interactive and debugging environment, nor do I think it should be.
How do people who do serious pkgsrc development separate the pkgsrc
bits they are working on from their running system, while keeping
convenient access to both?

--
IDL