Add support for the WebKit HTML rendering/layout engine

Packages describing “webkit” as local USE flag

Package “webkit” Flag Description
app-text/libgepub Build with GepubWidget based on Webkit
app-text/pdfpc Enable viewing Markdown notes (net-libs/webkit-gtk)
net-libs/libproxy Use libjavascriptcoregtk from net-libs/webkit-gtk for PAC parsing
dev-util/glade Build catalog support for net-libs/webkit-gtk:4 widgets.

All packages providing a “webkit” USE flag (13)