Sources here are from luasql git tag v2.4.0
(https://github.com/lunarmodules/luasql/tree/v2.4.0)
Some modifications have been done to them, but as of 08-Oct-22
all our modifications have been accepted to the upstream.
25-Oct-22: Local patch for fixing clang analyzer warnings has
           been applied. It's present also as a patch file
           clang_analyzer.patch

Only the files needed by freeciv are included here, not entire luasql
source directory hierarchy.
The ls_*.h files are our own additions to use those backends directly.
