coccinelle 1.0.0-rc21

Error log

The package failed to build. The error log from opam follows.

Opam plugin "depext" may require upgrading/reinstalling. Reinstall the plugin on the current switch? [Y/n] y
The following actions will be performed:
  - recompile opam-depext 1.2.3

<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
-> retrieved opam-depext.1.2.3  (cached)
-> removed   opam-depext.1.2.3
-> installed opam-depext.1.2.3
Done.

<><> opam-depext.1.2.3 installed successfully <><><><><><><><><><><><><><><><><>
=> opam-depext is unnecessary when used with opam >= 2.1. Please use opam install directly instead
# Run eval $(opam env) to update the current shell environment

<><> Carrying on to "opam depext -viy coccinelle.1.0.0-rc21 pcre.7.1.1 ocamlfind.1.9.6 ocamlbuild.0.14.3 menhir.20130116 conf-python-2-7-dev.1.0 conf-python-2-7.1.2 conf-pkg-config.3 conf-libpcre.1 camlp4.4.05+1" 

Since version 2.1, opam now handles external dependencies alongside OCaml ones, and the `depext` plugin interface is provided for backwards compatibility only. Consider using your usual `opam install` command to install both OCaml and system dependencies, or `opam install <pkg> --depext-only` if you want to only install external dependencies.
# Detecting depexts using vars: arch=x86_64, os=linux, os-distribution=debian, os-family=debian
[ERROR] No solution for coccinelle.1.0.0-rc21 & pcre.7.1.1 & ocamlfind.1.9.6 & ocamlbuild.0.14.3 & menhir.20130116 & conf-python-2-7-dev.1.0 & conf-python-2-7.1.2 & conf-pkg-config.3 & conf-libpcre.1 & camlp4.4.05+1:   * Missing dependency:
            - conf-python-2-7
            depends on the unavailable system package 'python2.7'. Use `--no-depexts' to attempt installation anyway, or it is possible that a depext package name in the opam file is incorrect.


Command failed: opam --cli=2.1 list --readonly --external '--resolve=coccinelle.1.0.0-rc21,pcre.7.1.1,ocamlfind.1.9.6,ocamlbuild.0.14.3,menhir.20130116,conf-python-2-7-dev.1.0,conf-python-2-7.1.2,conf-pkg-config.3,conf-libpcre.1,camlp4.4.05+1' --color=never returned 20