Support for MSVC's /Zi #1040
Description
ccache should support /Zi, which seems to be the most prolific switch used for debugging information.
Based on discussion held in https://developercommunity.visualstudio.com/t/absolute-paths-for-associated-pdb-files-are-record/573023 it appears the issue with /Zi is the fact that full file paths are being embedded in resulting objects, leading to possible caching issues. That same thread discusses a new switch having been added to MSVC 16.4p1, /d1trimfile which is capable of canonicalizing the paths into format that should pose no threat to caches.
I'm interested in trying to solve this issue, but not familiar with ccache code yet and somewhat time-constrained. I will try submitting something within a week or two or admitting defeat.