Reproduction steps:
1. Create a new project
2. Disable VR Built-in package
3. Install Post Processing package
4. Observe the Console output

Expected result: Console doesn't throw any errors
Actual result: Errors are thrown:
Library\PackageCache\com.unity.postprocessing@3.2.0\PostProcessing\Runtime\PostProcessLayer.cs(722,33): error CS0103: The name 'XRSettings' does not exist in the current context
Library\PackageCache\com.unity.postprocessing@3.2.0\PostProcessing\Runtime\PostProcessLayer.cs(722,67): error CS0103: The name 'XRSettings' does not exist in the current context

Reproducible with: PostProcessing 3.2.0 (2019.4.34f1, 2020.3.25f1. 2021.2.7f1,2022.1.0b2)
Not reproducible with: PostProcessing 3.1.1 (2019.4.34f1, 2020.3.25f1)