Hmm, all the files are there. Just did a fresh git pull and it compiles without issue.
git clone https://github.com/rascal71/node-open-mining-portal.git nomp
cd nomp
npm update
Probably a Debian/Ubuntu issue then, the "npm update" fails because there is a hard-coded "node" reference somewhere (it is "nodejs" in Debian), I symlinked it after the fact, but npm probably messed up itself anyway. The adapted C files from PrimeSoloMiner do work though (found a couple blocks). Thanks!