Ignore COQ_USE_DUNE when installing through opam
Ignore COQ_USE_DUNE when installing through opam

Using OPAM_PACKAGE_NAME to detect if we're in opam is the best
solution I know of.

ejgallego/coq,coq/coq,Zimmi48/coq,coq/coq,coq/coq,SkySkimmer/coq,Zimmi48/coq,SkySkimmer/coq,Zimmi48/coq,ejgallego/coq,SkySkimmer/coq,SkySkimmer/coq,coq/coq,ejgallego/coq,Zimmi48/coq,ejgallego/coq