Native bindings to the ARM_shader_framebuffer_fetch extension.

This extension enables fragment shaders to read existing framebuffer data as input. This permits use-cases such as programmable blending, and other operations that may not be possible to implement with fixed-function blending.

This extension also adds the ability to indicate that a shader should be run once per sample instead of once per pixel.

Reading framebuffer data as input in combination with multiple render targets (MRT) may not be supported by all implementations. This extension allows applications to query for this capability.

Requires GLES 2.0.