This transform generates code `if ( gamma != vec3(1., 1., 1.) )`
which is not compatible with Metal.
This patch adds an extra OCIO code processing which converts syntax
to a portable version. It only handles this specific case for the
processing performance reasons.
To reproduce the issue add the following look at the end of the
config.ocio:
```
- !<Look>
name: Grading
process_space: Filmic Log
description: TEST
transform: !<GroupTransform>
children:
- !<GradingPrimaryTransform>
style: log
contrast: {rgb: [0.7, 0.7, 0.7], master: 1}
saturation: 1.15
pivot: {contrast: -0.2}
```
Ref #110685
Pull Request: https://projects.blender.org/blender/blender/pulls/111231
259bfc4553