Concurrent Octave installations and mkoctfile

[Jordi Gutiérrez Hermoso]

Can I have a recommendation on how to have two separate Octave
installations and easily use mkoctfile for both of them?

Background information: I have the Debian packages installed mostly so
I can still check how things were in 3.2.4 when people ask about it,
but I mostly work myself with the development sources. At the moment I
need to test my implementation of bwlabeln, but for various reasons I
need the development sources to test on. While I can think of painful
fudging around with include and linking paths, I'm hoping there's a
simple solution that involves minimal fuss.

TIA,
- Jordi G. H.