Just in case anyone wants to try to reproduce this particular example:
1. Grab latest stable from here and untar it
https://webkitgtk.org/releases/
2. Run this included script, which is dnf aware, to install dependencies
./Tools/gtk/install-dependencies
3. Additional packages I had to install to get it to build
sudo dnf install ruby-devel openjpeg2-devel woff2-devel