Support RGB gl-tex-external stream consumers for StreamProducerNV12.

This makes it relatively simple to sample from a D3D11Texture of
arbitrary format.

From: https://bugzilla.mozilla.org/show_bug.cgi?id=1322746

BUG=angleproject:2233
TEST=angle_end2end_tests

Change-Id: I10cd3043b5cb0c5d36dd613467ba6c0ceadf41af
Reviewed-on: https://chromium-review.googlesource.com/758042
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libGLESv2/gen_proc_table.py b/src/libGLESv2/gen_proc_table.py
index 616b542..8f0fdc7 100644
--- a/src/libGLESv2/gen_proc_table.py
+++ b/src/libGLESv2/gen_proc_table.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!python
 # Copyright 2017 The ANGLE Project Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
@@ -65,7 +65,7 @@
 
 proc_data = [('    {"%s", P(%s)}' % (func, angle_func)) for func, angle_func in sorted(all_functions.iteritems())]
 
-with open(out_file_name, 'wt') as out_file:
+with open(out_file_name, 'wb') as out_file:
     output_cpp = template_cpp.format(
         script_name = sys.argv[0],
         data_source_name = data_source_name,