The latest download and install instructions are available in
https://docs.wxwidgets.org/3.1/plat_gtk_install.html
The wiki is a bit old so try following the above and consult the wiki for more details. BUT, follow the steps as per the docs NOT the wiki.
https://wiki.wxwidgets.org/Compiling_and_getting_started
However sometimes specially for new linux users it can become overwhelming and installation process can throw funny errors. So I have created a step by step process to hopefully help you compile wxwidgets. Enjoy :-)