build: enable WebKit dependency and get a full-feature Flatpak build!
The build has been fixed by a patch from Upstream: https://bugs.webkit.org/show_bug.cgi?id=156510 Note that WebKit takes hours to build, so if you just want to test Flatpak, you may prefer disable this module again. We now have a full-feature Flatpak build, except for libgudev, which means that special input devices probably won't work in the GIMP Flatpak. It is to be noted that Flatpak developers told me that libudev won't work inside the sandbox anyway. A portal will have to be implemented. See: https://github.com/flatpak/flatpak/issues/12#issuecomment-276016074