Enabling gst-build

​gst-build is the aggregated build system for GStreamer developers. If you want to test WebKit with bleeding edge GStreamer, this is the way. The Flatpak SDK has built-in support for gst-build:

$ git clone https://gitlab.freedesktop.org/gstreamer/gst-build.git ~/
$ export GST_BUILD_ARGS="-Dexamples=disabled -Dtests=disabled -Ddoc=disabled -Dqt5=disabled -Dgst-plugins-good:v4l2-gudev=disabled -Dpython=disabled -Dges=disabled -Ddevtools=disabled -Dintrospection=disabled -Dgst-plugins-bad:wpe=disabled"
$ export GST_BUILD_PATH=$HOME/gst-build
$ build-webkit ...
$ run-minibrowser ...

The GST_BUILD_PATH env var should be set both at build time and run time. The GST_BUILD_ARGS env var is optional, but recommended.