altgr-ergo 2.3.1

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 altgr-ergo.2.3.1 zarith.1.14 seq.base psmt2-frontend.0.4.0 ocplib-simplex.0.4.1 ocamlfind.1.9.6 num.1.5-1 menhirSdk.20211128 menhirLib.20211128 menhir.20211128 lablgtk.2.18.13 host-arch-x86_64.1 dune.2.9.3 conf-zlib.1 conf-pkg-config.3 conf-gtksourceview.2 conf-gtk2.1 conf-gmp.4 conf-autoconf.0.2 camlzip.1.12 camlp-streams.5.0.1 alt-ergo-parsers.2.3.1 alt-ergo-lib.2.3.1" 

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 altgr-ergo.2.3.1 & zarith.1.14 & seq.base & psmt2-frontend.0.4.0 & ocplib-simplex.0.4.1 & ocamlfind.1.9.6 & num.1.5-1 & menhirSdk.20211128 & menhirLib.20211128 & menhir.20211128 & lablgtk.2.18.13 & host-arch-x86_64.1 & dune.2.9.3 & conf-zlib.1 & conf-pkg-config.3 & conf-gtksourceview.2 & conf-gtk2.1 & conf-gmp.4 & conf-autoconf.0.2 & camlzip.1.12 & camlp-streams.5.0.1 & alt-ergo-parsers.2.3.1 & alt-ergo-lib.2.3.1:   * Missing dependency:
            - conf-gtksourceview
            depends on the unavailable system package 'libgtksourceview2.0-dev'. 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=altgr-ergo.2.3.1,zarith.1.14,seq.base,psmt2-frontend.0.4.0,ocplib-simplex.0.4.1,ocamlfind.1.9.6,num.1.5-1,menhirSdk.20211128,menhirLib.20211128,menhir.20211128,lablgtk.2.18.13,host-arch-x86_64.1,dune.2.9.3,conf-zlib.1,conf-pkg-config.3,conf-gtksourceview.2,conf-gtk2.1,conf-gmp.4,conf-autoconf.0.2,camlzip.1.12,camlp-streams.5.0.1,alt-ergo-parsers.2.3.1,alt-ergo-lib.2.3.1' --color=never returned 20