Convert from autotools to meson+ninja

[berylline]

As the title says.

For reference:

https://mesonbuild.com/Porting-from-autotools.html

https://mesonbuild.com/Reference-manual_functions.html

https://mesonbuild.com/Configuration.html

https://nibblestew.blogspot.com/2016/09/how-to-convert-autotools-project-to.html?m=1

https://github.com/mesonbuild/meson/blob/master/tools/ac_converter.py

As examples to look at:

https://github.com/swaywm/sway/blob/master/meson.build

https://github.com/swaywm/sway/blob/master/meson_options.txt

https://gitlab.freedesktop.org/wlroots/wlroots/-/blob/master/meson.build

https://gitlab.freedesktop.org/wlroots/wlroots/-/blob/master/meson_options.txt