if os.getenv "installcheck" == nil then

  -- Unless we're running inside `make installcheck`, add the dev-tree

  -- directories to the module search paths.

  local std = require "specl.std"

  local top_srcdir = os.getenv "top_srcdir" or "."

  local top_builddir = os.getenv "top_builddir" or "."

  package.path  = std.package.normalize (

		    top_builddir .. "/lib/?.lua",

		    top_srcdir .. "/lib/?.lua",

		    top_builddir .. "/lib/?/init.lua",

		    top_srcdir .. "/lib/?/init.lua",

		    package.path)

  package.cpath = std.package.normalize (

		    top_builddir .. "/ext/posix/.libs/?.so",

		    top_srcdir .. "/ext/posix/.libs/?.so",

		    top_builddir .. "/ext/posix/_libs/?.dll",

		    top_srcdir .. "/ext/posix/_libs/?.dll",

		    package.cpath)

end

local bit = require "bit32"

band, bnot, bor = bit.band, bit.bnot, bit.bor

badargs = require "specl.badargs"

hell    = require "specl.shell"

posix   = require "posix"

-- Allow user override of LUA binary used by hell.spawn, falling

-- back to environment PATH search for "lua" if nothing else works.

local LUA = os.getenv "LUA" or "lua"

-- Easily check for std.object.type compatibility.

function prototype (o)

  return (getmetatable (o) or {})._type or io.type (o) or type (o)

end

local function mkscript (code)

  local f = os.tmpname ()

  local h = io.open (f, "w")

  h:write (code)

  h:close ()

  return f

end

--- Run some Lua code with the given arguments and input.

-- @string code valid Lua code

-- @tparam[opt={}] string|table arg single argument, or table of

--   arguments for the script invocation

-- @string[opt] stdin standard input contents for the script process

-- @treturn specl.shell.Process|nil status of resulting process if

--   execution was successful, otherwise nil

function luaproc (code, arg, stdin)

  local f = mkscript (code)

  if type (arg) ~= "table" then arg = {arg} end

  local cmd = {LUA, f, unpack (arg)}

  -- inject env and stdin keys separately to avoid truncating `...` in

  -- cmd constructor

  cmd.stdin = stdin

  cmd.env = {

    LUA_CPATH    = package.cpath,

    LUA_PATH     = package.path,

    LUA_INIT     = "",

    LUA_INIT_5_2 = ""

  }

  local proc = hell.spawn (cmd)

  os.remove (f)

  return proc

end

-- Use a consistent template for all temporary files.

TMPDIR = posix.getenv ("TMPDIR") or "/tmp"

template = TMPDIR .. "/luaposix-test-XXXXXX"

-- Allow comparison against the error message of a function call result.

function Emsg (_, msg) return msg or "" end

-- Collect stdout from a shell command, and strip surrounding whitespace.

function cmd_output (cmd)

  return hell.spawn (cmd).output:gsub ("^%s+", ""):gsub ("%s+$", "")

end

local st = require "posix.sys.stat"

local stat, S_ISDIR = st.lstat, st.S_ISDIR

-- Recursively remove a temporary directory.

function rmtmp (dir)

  for f in posix.files (dir) do

    if f ~= "." and f ~= ".." then

      local path = dir .. "/" .. f

      if S_ISDIR (stat (path).st_mode) ~= 0 then

        rmtmp (path)

      else

        os.remove (path)

      end

    end

  end

  os.remove (dir)

end

-- Create an empty file at PATH.

function touch (path) io.open (path, "w+"):close () end

-- Format a bad argument type error.

local function typeerrors (fname, i, want, field, got)

  return {

    badargs.format ("?", i, want, field, got),   -- LuaJIT

    badargs.format (fname, i, want, field, got), -- PUC-Rio

  }

end

function init (M, fname)

  return M[fname], function (...) return typeerrors (fname, ...) end

end