add std++ 1.2.0
add std++ 1.2.0

gmalecha/opam-coq-archive,mattam82/coq-opam-archive,mattam82/coq-opam-archive,gmalecha/opam-coq-archive,coq/opam-coq-archive,mattam82/coq-opam-archive,gmalecha/opam-coq-archive