anchor.diff:                 /LIB, and /BIN options.
   /INC [dir]     Location of Lua includes - e.g. c:\lua\5.1\include
                  If provided overrides sub directory found using /LUA.
  -/LIB [dir]     Location of Lua libraries -e.g. c:\lua\5.1\lib
  +/LIB [dir]     Location of Lua libraries (.dll) - e.g. c:\lua\5.1\lib
                  If provided overrides sub directory found using /LUA.
   /BIN [dir]     Location of Lua executables - e.g. c:\lua\5.1\bin
                  If provided overrides sub directory found using /LUA.
  -
  +/L             Install LuaRocks' own copy of Lua even if detected,
  +               this will always be a 5.1 installation.
  +               (/LUA, /INC, /LIB, /BIN cannot be used with /L)
  +
  +Compiler configuration:
   /MW            Use mingw as build system instead of MSVC
   
  +Other options:
  +/CONFIG [dir]  Location where the config file should be installed.
  +               Default is same place of installation
   /FORCECONFIG   Use a single config location. Do not use the
                  LUAROCKS_CONFIG variable or the user's home directory.
                  Useful to avoid conflicts when LuaRocks
                  is embedded within an application.
  -
   /F             Remove installation directory if it already exists.
  -
   /R             Load registry information to register '.rockspec'
                  extension with LuaRocks commands (right-click).
   
  
positive.code: 	vars.LUA_LIBDIR = vars.LIBDIR
  	vars.LUA_INCDIR = vars.INCDIR
  	vars.LUA_LIBNAME = "lua5.1.lib"
      vars.LUA_RUNTIME = "MSVCR80"
      vars.UNAME_M = "x86"
  else
      vars.UNAME_M = get_architecture()
  	print(S[[
  
  Will configure LuaRocks with the following paths:
  
negative.code: 
  
  local function get_runtime()
  	local f
  	vars.LUA_RUNTIME, f = pe.msvcrt(vars.LUA_BINDIR.."\\"..vars.LUA_INTERPRETER)
  	if type(vars.LUA_RUNTIME) ~= "string" then
  		-- analysis failed, issue a warning
  		vars.LUA_RUNTIME = "MSVCR80"
  		print("*** WARNING ***: could not analyse the runtime used, defaulting to "..vars.LUA_RUNTIME)
  	else
  		print("    "..f.." uses "..vars.LUA_RUNTIME..".DLL as runtime")
  	end
  	return true
  end
  
  local function get_architecture()
  	-- detect processor arch interpreter was compiled for
  	local proc = (pe.parse(vars.LUA_BINDIR.."\\"..vars.LUA_INTERPRETER) or {}).Machine
  	if not proc then
  		die("Could not detect processor architecture used in "..vars.LUA_INTERPRETER)
  	end
  	proc = pe.const.Machine[proc]  -- collect name from constant value
  	if proc == "IMAGE_FILE_MACHINE_I386" then
  		proc = "x86"
  	else
  		proc = "x86_64"
  	end
  	return proc
  end
  
  local function look_for_lua_install ()
  