intel: make intel_ir opaque

It is just gl_shader_program in the end, and we want gl_shader_program to be
opaque.  This also forces the driver to correctly use intel_pipeline_shader
instead of intel_ir.

With the change, xglCreateShader() now asks the compiler to compile BIL into
intel_ir.  Later when the pipeline is created, the intel_ir is passed to the
compiler again to generate the binary kernel as well as metadata.
diff --git a/icd/intel/cmd_pipeline.c b/icd/intel/cmd_pipeline.c
index eb3e5c2..676c491 100644
--- a/icd/intel/cmd_pipeline.c
+++ b/icd/intel/cmd_pipeline.c
@@ -26,6 +26,7 @@
  *   Courtney Goeltzenleuchter <courtney@lunarg.com>
  */
 
+#include <stdio.h> /* for printf */
 #include "genhw/genhw.h"
 #include "dset.h"
 #include "img.h"