As of node 9.3.0, a bug was fixed preventing builds with gcc. Don't prevent gcc
from building it now.
I don't see anything in the node source that's platform specific. Granted, I haven't test-compiled for mips, so it might be broken, but gcc is no longer the limiting factor (I only have powerpc machines).
Testing further, on my powerpcspe machine, It looks like node.js needs a little work for the configure script to build on powerpc, powerpcspe, and possibly mips. So I'll just add powerpc64 to the ONLY_FOR_ARCHS line instead.