Compiling with different location of dependencies in the system (e.g. OSX)

[an0nym05]

I've realized expected configuration doesn't work in some cases (e.g. on OSX with brew):

{port_env, [{"CFLAGS", "$CFLAGS -I/usr/local/include -I./include -g -Wall -Werror"},
            {"LDFLAGS", "$LDFLAGS -L/usr/local/lib -lzmq"}]}.

Do you think it would be more flexible to rely on the output of pkg-config for compiler/linker flags?
The current workaround for Elixir project I did as below (works in my library, and in an app that depends on my library that uses erlzmq):

  defp deps do
    [
      ...
      {:erlzmq,
       git: "https://github.com/lukaszsamson/erlzmq",
       tag: "v4.1.4",
       system_env: erlzmq_system_env()},
       ...
    ]
  end

  defp erlzmq_system_env() do
    {:ok, pid} = StringIO.open("")

    Mix.Shell.cmd("pkg-config --cflags libzmq", [], fn output ->
      IO.write(pid, String.replace(output, "\n", ""))
    end)

    cflags = StringIO.flush(pid)

    Mix.Shell.cmd("pkg-config --libs libzmq", [], fn output ->
      IO.write(pid, String.replace(output, "\n", ""))
    end)

    {:ok, {_, ldflags}} = StringIO.close(pid)

    [
      {"CFLAGS", cflags},
      {"LDFLAGS", ldflags}
    ]
  end

[lukaszsamson]

I'm sure there are better ways. The current state comes from the original project with minor changes for BSD compatibility (https://github.com/lukaszsamson/erlzmq/pull/5/files). Would you mind creating a PR?

[an0nym05]

Sure, will prepare one today.