We now detect at runtime which sync features to use, which
allows us to remove a lot of the compile-time configuration
options. There is still one option though, to disable
KHR_fence_sync on some devices (which are more efficient
without it).
- added a backdoor to get the vendor's EGL strings
the new logic is:
- use always ANDROID_native_fence_sync if available
- fallback to KHR_fence_sync if available and not disabled
by the compile-time option
- use KHR_wait_sync if available and either of the above is
enabled
Change-Id: I9c4b49d9ff1151faf902cc93bd53ea5f205aaabf
