Add an option to support for GL_OES_EGL_image_external.

Comes with this extension is the new sampler type samplerExternalOES.

ANGLEBUG=175
TEST=compile the attached shader file
Review URL: http://codereview.appspot.com/4809076

git-svn-id: https://angleproject.googlecode.com/svn/trunk@728 736b8ea6-26fd-11df-bfd4-992fa37f6226
diff --git a/src/compiler/Compiler.cpp b/src/compiler/Compiler.cpp
index 0456fa3..16b7bd9 100644
--- a/src/compiler/Compiler.cpp
+++ b/src/compiler/Compiler.cpp
@@ -19,6 +19,7 @@
 {
     TIntermediate intermediate(infoSink);
     TExtensionBehavior extBehavior;
+    InitExtensionBehavior(resources, extBehavior);
     // The builtins deliberately don't specify precisions for the function
     // arguments and return types. For that reason we don't try to check them.
     TParseContext parseContext(symbolTable, extBehavior, intermediate, type, spec, 0, false, NULL, infoSink);