Annotation For xvfs-create-synthetic

Origin for each line in xvfs-create-synthetic from check-in f4ea8e39b6:

c8742de968 2019-09-20    1: #! /usr/bin/env tclsh
c8742de968 2019-09-20    2: 
c8742de968 2019-09-20    3: set sourceDirectory [file dirname [file normalize [info script]]]
c8742de968 2019-09-20    4: lappend auto_path [file join $sourceDirectory lib]
c8742de968 2019-09-20    5: package require xvfs
c8742de968 2019-09-20    6: 
c8742de968 2019-09-20    7: proc ::xvfs::callback::setOutputFileName {args} {
c8742de968 2019-09-20    8: 	return "/"
c8742de968 2019-09-20    9: }
c8742de968 2019-09-20   10: 
c8742de968 2019-09-20   11: proc ::xvfs::callback::addOutputFiles {fsName} {
c8742de968 2019-09-20   12: 	::xvfs::processFile $fsName "" "" {
c8742de968 2019-09-20   13: 		type directory
c8742de968 2019-09-20   14: 		children "foo"
c8742de968 2019-09-20   15: 	}
c8742de968 2019-09-20   16: 	::xvfs::processFile $fsName "" "foo" {
c8742de968 2019-09-20   17: 		type file
c8742de968 2019-09-20   18: 		fileContents "abc"
c8742de968 2019-09-20   19: 	}
f4ea8e39b6 2019-09-20   20: 	::xvfs::processFile $fsName "./xvfs-create-synthetic" "xvfs-create-synthetic" {
f4ea8e39b6 2019-09-20   21: 		type file
f4ea8e39b6 2019-09-20   22: 	}
f4ea8e39b6 2019-09-20   23: 	return [list "" "foo" "xvfs-create-synthetic"]
c8742de968 2019-09-20   24: }
c8742de968 2019-09-20   25: 
c8742de968 2019-09-20   26: ::xvfs::run --directory [pwd] --name synthetic