Reasoning being:
* The result_set and other APIs are nicer to use.
* We use mariadb on our server rather than mysql, so this would minimize the chance of any incompatibilities.
* The mysql C++ connector 1.1 isn't compatible with with c++17 (https://stackoverflow.com/q/47284705).
While I understand the reason it's here, it's been over a decade, no other user handlers have been added, and there's no indication any others will be added. Therefore, it doesn't seem like there's much of a reason to keep this code around.
* Use separate files to build scons and to build lua for cmake
Move lists of source files into their own directory
Make scons use the lists of source files
Move lua build step to src/SConscript and delete src/lua/SConscript
Make cmake use the separate file with the list of lua sources to build
* Finish changing over to source lists
scons
move source files from libraries that don't appear in cmake over to existing source lists - libcampaignd, libcutter, libdummy_video, libtest_utils
add the defines FIFODIR and WESNOTH_PATH to all compiled source files, as cmake does, and move the single files those defines had previously been defined on into the source lists
remove WESNOTH_PREFIX, as not used
added schema_validator sources from cmake
added OBJPREFIX to - cutter, exploder, campaignd, schema_generator, schema_validator
cmake
change over to using the source lists
move source files from libraries that don't appear in scons over to existing source lists - wesnoth-gui_types, wesnoth-gui_event, wesnoth-gui_iterator, wesnoth-gui_placer, wesnoth-gui_tooltip, wesnoth-gui_widget, wesnoth-gui_widget_definition, wesnoth-gui1_widgets, wesnoth-schema_validator
