cmake: Add option waffle_has_surfaceless_egl (v2)

This patch contains just the CMake changes for the new surfaceless_egl
platform. Code will come in the following patches.

v2:
  - Fix copy-paste error. s/Darwin/Windows/. (for emil)

Cc: Gurchetan Singh <gurchetansingh@chromium.org>
Cc: Haixia Shi <hshi@chromium.org>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>