Install missing pc dependency for Elixir compatibility

[arturz]

Description

Mix Elixir build tool does not support Rebar3 plugins, and pc (port compiler) plugin is required.

Fix

This PR adds pc as a dependency, making eiconv work with Elixir applications.

How to reproduce?

1. Create a new Elixir application.
2. Add {:eiconv, "~> 1.0"} to deps.
3. Run DEBUG=1 mix compile.

Error below is produced:

===> Getting definition for package pc from repo hexpm (#{name => <<"hexpm">>,repo_verify_origin => true,
         repo_name => <<"hexpm">>,repo_url => <<"https://repo.hex.pm">>,
         repo_organization => undefined,api_url => <<"https://hex.pm/api">>,
         repo_verify => true})
===> hex_repo:get_package failed for package <<"pc">>: badarg
===> throw {error,{rebar_app_utils,{missing_package,<<"pc">>,undefined}}} [{rebar_app_utils,
                                                                            update_source,
                                                                            3,
                                                                            [{file,
                                                                              "/rebar3/apps/rebar/src/rebar_app_utils.erl"},
                                                                             {line,
                                                                              335}]},
                                                                           {rebar_prv_install_deps,
                                                                            '-handle_profile_level/7-lc$^0/1-0-',
                                                                            3,
                                                                            [{file,
                                                                              "/rebar3/apps/rebar/src/rebar_prv_install_deps.erl"},
                                                                             {line,
                                                                              178}]},
                                                                           {rebar_prv_install_deps,
                                                                            handle_profile_level,
                                                                            7,
                                                                            [{file,
                                                                              "/rebar3/apps/rebar/src/rebar_prv_install_deps.erl"},
                                                                             {line,
                                                                              179}]},
                                                                           {rebar_plugins,
                                                                            handle_plugin,
                                                                            5,
                                                                            [{file,
                                                                              "/rebar3/apps/rebar/src/rebar_plugins.erl"},
                                                                             {line,
                                                                              121}]},
                                                                           {rebar_plugins,
                                                                            '-handle_plugins/4-fun-0-',
                                                                            5,
                                                                            [{file,
                                                                              "/rebar3/apps/rebar/src/rebar_plugins.erl"},
                                                                             {line,
                                                                              102}]},
                                                                           {lists,
                                                                            foldl,
                                                                            3,
                                                                            [{file,
                                                                              "lists.erl"},
                                                                             {line,
                                                                              1594}]},
                                                                           {rebar_plugins,
                                                                            handle_plugins,
                                                                            4,
                                                                            [{file,
                                                                              "/rebar3/apps/rebar/src/rebar_plugins.erl"},
                                                                             {line,
                                                                              101}]},
                                                                           {lists,
                                                                            foldl,
                                                                            3,
                                                                            [{file,
                                                                              "lists.erl"},
                                                                             {line,
                                                                              1594}]}]
===> Errors loading plugin pc. Run rebar3 with DEBUG=1 set to see errors.
===> Expanded command sequence to be run: []
===> Running provider: do
===> Expanded command sequence to be run: [app_discovery,{bare,compile}]
===> Running provider: app_discovery
===> Found top-level apps: [eiconv]
        using config: [{src_dirs,["src"]},{lib_dirs,["apps/*","lib/*","."]}]
===> Getting definition for package pc from repo hexpm
===> hex_repo:get_package failed for package <<"pc">>: badarg
===> throw {error,{rebar_app_utils,{missing_package,<<"pc">>,undefined}}} [{rebar_app_utils,
                                                                            update_source,
                                                                            3,
                                                                            [{file,
                                                                              "/rebar3/apps/rebar/src/rebar_app_utils.erl"},
                                                                             {line,
                                                                              335}]},
                                                                           {rebar_prv_install_deps,
                                                                            '-handle_profile_level/7-lc$^0/1-0-',
                                                                            3,
                                                                            [{file,
                                                                              "/rebar3/apps/rebar/src/rebar_prv_install_deps.erl"},
                                                                             {line,
                                                                              178}]},
                                                                           {rebar_prv_install_deps,
                                                                            handle_profile_level,
                                                                            7,
                                                                            [{file,
                                                                              "/rebar3/apps/rebar/src/rebar_prv_install_deps.erl"},
                                                                             {line,
                                                                              179}]},
                                                                           {rebar_plugins,
                                                                            handle_plugin,
                                                                            5,
                                                                            [{file,
                                                                              "/rebar3/apps/rebar/src/rebar_plugins.erl"},
                                                                             {line,
                                                                              121}]},
                                                                           {rebar_plugins,
                                                                            '-handle_plugins/4-fun-0-',
                                                                            5,
                                                                            [{file,
                                                                              "/rebar3/apps/rebar/src/rebar_plugins.erl"},
                                                                             {line,
                                                                              102}]},
                                                                           {lists,
                                                                            foldl,
                                                                            3,
                                                                            [{file,
                                                                              "lists.erl"},
                                                                             {line,
                                                                              1594}]},
                                                                           {rebar_plugins,
                                                                            handle_plugins,
                                                                            4,
                                                                            [{file,
                                                                              "/rebar3/apps/rebar/src/rebar_plugins.erl"},
                                                                             {line,
                                                                              101}]},
                                                                           {lists,
                                                                            foldl,
                                                                            3,
                                                                            [{file,
                                                                              "lists.erl"},
                                                                             {line,
                                                                              1594}]}]
===> Errors loading plugin pc. Run rebar3 with DEBUG=1 set to see errors.
===> Running provider: {bare,compile}
===> Compile (untagged)
===> Running hooks for compile in app eiconv (/Users/az/testapp/deps/eiconv) with configuration:
===>    {provider_hooks, [{pre, [{pc,compile}]}]}.
===> Running provider: {pc,compile}
===> Unable to run pre hooks for 'compile', command 'compile' in namespace 'pc' not found.
===> Unable to run pre hooks for 'compile', command 'compile' in namespace 'pc' not found.
** (Mix) Could not compile dependency :eiconv, "/Users/az/.asdf/installs/elixir/1.16.2-otp-26/.mix/elixir/1-16/rebar3 bare compile --paths /Users/az/testapp/_build/dev/lib/*/ebin" command failed. Errors may have been logged above. You can recompile this dependency with "mix deps.compile eiconv --force", update it with "mix deps.update eiconv" or clean it with "mix deps.clean eiconv"

This PR fixed that issue.

[mmzeeman]

Thanks.