This package changed from autoconf to cmake during the last recipe
upgrade. This made the existing EXTRA_OECONF, which disabled wekbit
support among other things, non-functional, which in turn, broke the
build.
This patch disables webkit in a CMAKE way by adding EXTRA_OECMAKE to
the cmake class description, and setting it to "-DWEBKIT=no" in the
libproxy recipe and also reproduces the EXTRA_OECONF settings.
