Opam does not accept coq-stdpp for Coq 8.7
https://github.com/coq/opam-coq-archive/blob/master/released/packages/coq-stdpp/coq-stdpp.1.0.0/opam
Everything compiles fine.
https://github.com/coq/opam-coq-archive/blob/master/released/packages/coq-stdpp/coq-stdpp.1.0.0/opam
Everything compiles fine.