Enable the use of samplerExternalOES.

Change-Id: Iabafc06d073c99f9cc5b2c62ed83eff4862bc2cc
Reviewed-on: https://swiftshader-review.googlesource.com/2684
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>
diff --git a/src/OpenGL/libGLESv2/Shader.cpp b/src/OpenGL/libGLESv2/Shader.cpp
index 81616c3..247c88d 100644
--- a/src/OpenGL/libGLESv2/Shader.cpp
+++ b/src/OpenGL/libGLESv2/Shader.cpp
@@ -171,6 +171,7 @@
 	resources.MaxDrawBuffers = MAX_DRAW_BUFFERS;
 	resources.OES_standard_derivatives = 1;
 	resources.OES_fragment_precision_high = 1;
+	resources.OES_EGL_image_external = 1;
 	resources.MaxCallStackDepth = 16;
 	assembler->Init(resources);