net-libs/webkit-gtk: security bump to 2.26.2

net-libs/webkit-gtk: security bump to 2.26.2

* Add unconditional sandboxing support, if available for the arch.
* Switch IUSE=gles2 to IUSE=gles2-only, as it is an alternative to
  USE=opengl, not a co-existing one.
* USE=wayland now requires wpebackend-fdo and co for
  accelerated compositing under wayland, if opengl is enabled.
* Re-enable IUSE=+jumbo-build for unified source builds - it was
  unconditionally enabled before, but with 2.26 disabling it
  finally seems to work. Disabling it seems to result in a 2MB
  larger library and over twice the compile time, but it may be
  crucial to low RAM systems to be able to even build webkit-gtk
  at all.
* gtk2 plugin process is now dropped upstream - no more
  adobe-flash support.
* geoclue is a runtime-only depend now (dbus interface).
* GCC/clang checks updated to the best of my understanding.
* Added ruby:2.7 support for the build-time depend on it.

Bug: https://bugs.gentoo.org/699156
Package-Manager: Portage-2.3.79, Repoman-2.3.12
Signed-off-by: Mart Raudsepp <leio@gentoo.org>