[mkgmap-dev] Commit r4391: Fix error with option --precomp-sea, probably related to multi-threading.

Version mkgmap-r4391 was committed by gerd on Thu, 12 Dec 2019 Fix error with option --precomp-sea, probably related to multi-threading. For now, Revert all refactoring changes in SeaGenerator.java made in r4382. http://www.mkgmap.org.uk/websvn/revision.php?repname=mkgmap&rev=4391