The package isn't in the default 'Woody' repository. I was trying to install
gddrescue_1.21-1_i386.deb from
http://mirror.aarnet.edu.au/debian stable main contrib non-free
as per instructions on
https://owenthe.ninja/2016/07/getting-apt-on-damn-small-linux-in-2016/.
(The other mirror, http://mirror.linux.org.au/debian stable main contrib non-free, looks to be identical.) I guess that's where the problems originate. I'll post an update after I come up to speed on compiling.
Thanks for clarifying my direction.
"If you think education is expensive, try ignorance!"