Which version of the CompCert compiler is required by uberspark? The text states v3.0.1, while the listing example shows v3.1 of CompCert.
It should be v3.1
Is this the current generation toolkit or the nextgen toolkit docs you are referring to?
Current generation toolkit documentation docs.
Also, you might want to add a
eval `opam config env` after the opam installs in your example listings.