EasyClangComplete: No error but no autocompletion on Apple Clang version > 7.3

I haven’t yet set up the include_dirs, which is the crux of the problem, but this is a bit onerous for the projects I’m working with and I’m not even seeing completions based on the default settings yet (i.e. from the h files in the file folder and its parent folder).

Here are my current user settings:

{
  "std_flag" : "-std=c++03",
  "auto_set_sublime_triggers" : false,
  "auto_complete_triggers" :
  [
    {
      "characters": ".:>",
      "selector": "source.c++ - string - comment - constant.numeric"
    }
  ]
}

On a related note, since my project has 4 folders, where does $project_base_path point to?

proj.sublime-project looks something like this:

{
    "folders":
    [
        {
            "path": "to/src"
        },
        {
            "path": "to/other/src"
        },
        {
            "path": "to/yet/another/src"
        }
    ]
}

I’m hoping to coax EasyClangComplete to give me completions, but note that my projects are probably not clang compatible. I build them using VxWorks 6.4/6.8 that run modified versions of GCC 3.4.4/4.1.2.