conf-llvm 8.0.0

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 1.2.1-1

<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
-> retrieved opam-depext.1.2.1-1  (cached)
-> removed   opam-depext.1.2.1-1
-> installed opam-depext.1.2.1-1
Done.

<><> opam-depext.1.2.1-1 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 llvm.8.0.0 stdlib-shims.0.3.0 ocamlfind.1.9.6 integers.0.7.0 dune-configurator.3.13.0 dune.3.13.0 ctypes.0.21.1 csexp.1.5.2 conf-python-2-7.1.2 conf-llvm.8.0.0 conf-cmake.1 conf-bash.1 bigarray-compat.1.1.0" 

You are using opam 2.1+, where external dependency handling has been integrated: consider calling opam directly, the 'depext' plugin interface is provided for backwards compatibility only
# Detecting depexts using vars: arch=x86_64, os=linux, os-distribution=debian, os-family=debian
[ERROR] No solution for llvm.8.0.0 & stdlib-shims.0.3.0 & ocamlfind.1.9.6 & integers.0.7.0 & dune-configurator.3.13.0 & dune.3.13.0 & ctypes.0.21.1 & csexp.1.5.2 & conf-python-2-7.1.2 & conf-llvm.8.0.0 & conf-cmake.1 & conf-bash.1 & bigarray-compat.1.1.0:   * Missing dependency:
            - conf-llvm = 8.0.0
            depends on the unavailable system package 'llvm-8-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=llvm.8.0.0,stdlib-shims.0.3.0,ocamlfind.1.9.6,integers.0.7.0,dune-configurator.3.13.0,dune.3.13.0,ctypes.0.21.1,csexp.1.5.2,conf-python-2-7.1.2,conf-llvm.8.0.0,conf-cmake.1,conf-bash.1,bigarray-compat.1.1.0' returned 20