weston: upgrade to 4.0.0
Official announcement:
https://lists.freedesktop.org/archives/wayland-devel/2018-April/037768.html
Dropped previously backported fix-missing-header.patch and
weston-gl-renderer-Set-pitch-correctly-for-subsampled-textures.patch
Refresh remaining local patches.
Modify 0001-weston-launch-Provide-a-default-version-that-doesn-t.patch with
changes to apply against the new code base.
Support for libunwind was dropped in
bb707dc0fe331c9af112a0552b7aa6fde755dd83:
https://cgit.freedesktop.org/wayland/weston/commit/?id=
bb707dc0fe331c9af112a0552b7aa6fde755dd83
Extract major version for referring to libweston-4 helper libraries.
Signed-off-by: Denys Dmytriyenko <denys@ti.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
