RCG: cherry pick two items from master into branch-4.2

$bdroot is a reference to the current mdl file. It's used only in newer (>=2017) matlab versions.

post process script changed to replace $bdroot with current file name, rather than truncated system name. Also, a single typo was fixed.

2. fix deep link problems that cause infinite library reference recursion when parsing mdl files.

assigned to @ezekiel.dohmen

mentioned in issue #383 (closed)

mentioned in commit 001267ab

merged