How to resume a broken run of bootstrap

[Mayuresh <mayuresh%acm.org@localhost>]

I am trying to use pkgsrc/bootstrap on Raspbian.

When I realized I should have given it --make-jobs 8 and broke it, I found
that it insists on deleting the "work" directory.

After deleting work directory and resuming, it complained about packages
already installed etc. I tried installing those manually, though shlock
and pkg_install seemed to show cross dependency.

So I deleted /var/db/pkg, /usr/pkg and work and resumed again. But that
wasted a lot of time.

Is there any more efficient way to resume in case bootstrap is either
killed or comes out with errors?

Mayuresh.