anchor.diff:  	return nil
   end
   
  -local function get_visual_studio_directory()
  +local function get_visual_studio_directory_from_registry()
   	assert(type(vars.LUA_RUNTIME)=="string", "requires vars.LUA_RUNTIME to be set before calling this function.")
   	local major, minor = vars.LUA_RUNTIME:match('VCR%u*(%d+)(%d)$') -- MSVCR<x><y> or VCRUNTIME<x><y>
   	if not major then 
  
positive.code: 	assert(type(vars.UNAME_M) == "string", "requires vars.UNAME_M to be set before calling this function.")
  	local x64 = vars.UNAME_M=="x86_64"
  
  	-- 1. try visual studio command line tools
  	local vcdir = get_visual_studio_directory()
  	if vcdir then
  		local vcvars_bats = {
  			x86 = {
  
negative.code: 		end
  	end
  
  	-- 3. try for Windows SDKs command line tools.
  	local wsdkdir = get_windows_sdk_directory()
  	if wsdkdir then
  		local setenv = wsdkdir.."Bin\\SetEnv.cmd"
  