Emil Velikov authored Oct 21, 2016 and Adam Jackson committed Oct 25, 2016

The extension does not exist in the registry, thus needs to know they're
using EGL 1.5 in order to determine the eglGetPlatformDisplay function
pointer is valid.

Thus brings us into some lovely circular dependency.

Since mesa won't be able (in the foreseeable future) to export the KHR
flavour of extension (another way one could assume that EGL 1.5 is
available) just drop all the heuristics and use the
EGL_EXT_platform_base extension.

In practise (checked with the Mali driver) any EGL 1.5 driver will
advertise support for EGL_EXT_platform_base.

Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>