`libcurl` & `libcairo` are also optional and their usage can now be optionally disabled (along with `libmemcached` & `librados`.)
* No longer test macOS Autotools building
* Updates are no longer available for CentOS Stream 8 since the end of May 2024
* Updates will cease being available for CentOS 7 at the end of June 2024
* Fixed `render_list` build needs `libm`
* Added tests
* Updated man page
* Created function to set double
* Cleaned up / optimized a bit
* Removed `--dont-render` option
And setting it to `0`, no longer requiring defining it everywhere except in foreground executables as needed.
_Also_:
* Require `GLib` >= `v2.50`
* Needed for [g_log_writer_standard_streams](https://docs.gtk.org/glib/func.log_writer_standard_streams.html)
* Set FreeBSD job `BUILD_PARALLEL_LEVEL` & `TEST_PARALLEL_LEVEL` environment variables via `run`
* Rather than hard-coding them
* Report coverage for almost all jobs
* Some jobs fail and are omitted
* Add more tests to `gen_tile_test.cpp`
* Also lightly cleaned up formatting
* Clean up cmake/* files
* So they don't report an empty version
* Remove commented `check_*` lines from `CMakeLists.txt` file
* These were left over from the initial CMake support implementation
For linting `CMakeLists.txt` & `*.cmake` files (`cmakelint`) as well as various other formats such as `HTML`, `MarkDown` & `YAML` (`prettier`.)
### Also:
* Upgrade `actions/checkout` from `v3` to `v4`
* Output coverage summary to GitHub Job step summary
* Minor build docs cleanup for `CentOS` & `FreeBSD`
