On r228866: <https://trac.webkit.org/changeset/228866> an include of <gst/gl/wayland/gstgldisplay_wayland.h> was added, which then r229022 <https://trac.webkit.org/changeset/229022> forgot to remove. The main issue with this include is that is not available on the gstreamer versions shipped by Debian stretch, which makes the build fail unless the JHBuild is used.
Created attachment 339318 [details] Patch
Comment on attachment 339318 [details] Patch Clearing flags on attachment: 339318 Committed r231249: <https://trac.webkit.org/changeset/231249>
All reviewed patches have been landed. Closing bug.