As @fuzzyTew said, this appears to be a bug with 18.1.40, but as it’s limited to the documentation it should be safe enough to patch yourself. There’s two simple ways to do this. By far the easier is to just create the directories it wants in the docs directory, easily accomplished with mkdir db-18.1.40/docs/bdb-sql db-18.1.40/docs/gsg_db_server. This will leave you with a random pair of empty directories in your documentation folder, but I can’t find any references even within the documentation itself that uses them so it should be safe enough. Alternatively, you can remove them from the Makefile after running configure using sed -i.bak -e 's: bdb-sql : :' -e 's: gsg_db_server : :' Makefile. Personally, I prefer just making the empty directories as it’s nearly impossible for that to go wrong.
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