[mkgmap-dev] Commit r4504: Add robustness for length style function. Nested relations may form loops like A has member B and B has member A.

Version mkgmap-r4504 was committed by gerd on Wed, 27 May 2020 Add robustness for length style function. Nested relations may form loops like A has member B and B has member A. http://www.mkgmap.org.uk/websvn/revision.php?repname=mkgmap&rev=4504