Problems compiling "fs" dependency on an Alpine Linux

I’m trying to compile my phoenix app on an Alpine Linux image but can’t seem to get past this error:

# mix deps.compile
==> fs (compile)
ERROR: compile failed while processing /teste/deps/fs: {'EXIT',{undef,[{erl_syntax,type,[{attribute,1,module,fs_sup}],[]},
                {rebar_erlc_compiler,parse_attrs,2,
                                     [{file,"src/rebar_erlc_compiler.erl"},
                                      {line,619}]},
                {rebar_erlc_compiler,modify_erlcinfo,4,
                                     [{file,"src/rebar_erlc_compiler.erl"},
                                      {line,451}]},
                {rebar_erlc_compiler,'-update_erlcinfo_fun/2-fun-0-',4,
                                     [{file,"src/rebar_erlc_compiler.erl"},
                                      {line,401}]},
                {lists,foldl,3,[{file,"lists.erl"},{line,1263}]},
                {rebar_erlc_compiler,init_erlcinfo,2,
                                     [{file,"src/rebar_erlc_compiler.erl"},
                                      {line,391}]},
                {rebar_erlc_compiler,doterl_compile,4,
                                     [{file,"src/rebar_erlc_compiler.erl"},
                                      {line,302}]},
                {rebar_core,run_modules,4,
                            [{file,"src/rebar_core.erl"},{line,493}]}]}}
** (Mix) Could not compile dependency :fs, "/root/.mix/rebar compile skip_deps=true deps_dir="/teste/_build/dev/lib"" command failed. You can recompile this dependency with "mix deps.compile fs", update it with "mix deps.update fs" or clean it with "mix deps.clean fs"

Can anyone figure out what the actual error is trying to tell me? I can compile this fine on a Ubuntu image with Erlang 19 and Elixir 1.3. Maybe I have a missing package?

Thanks.

it seems you are missing an erlang package. Maybe parse_tools? Or some sort of erlang-dev.

Not those ones… I have installed erlang erlang-crypto erlang-sasl erlang-dev erlang-parsetools.

That’s the one missing. Here is the source: Erlang -- erl_syntax

It seems it belongs to the syntax_tools applications. Do you have it installed?

Thank you! Indeed it was “erlang-syntax-tools” that was missing.