configure: Allow android as an EGL platform

I'm working on radeonsi support in the Chrome OS Android container
(ARC++).  Mesa in ARC++ uses autotools instead of Android.mk, but all
the necessary EGL bits are there, so the existing check is too strict.

Signed-off-by: Benjamin Gordon <bmgordon@chromium.org>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
1 file changed