Brings the number in line with that reported by Finder. --- fstatvfs on macOS returns the immediately available space on-disk, but the Finder shows a different number, which accounts for "reclaimable" space (i.e., that used by purgeable caches and other temporary data). That reclaimable space is available for Wine to use, and the difference between the two figures can sometimes be dramatic. We should ideally show what Finder shows. It is unfortunate to have to resort to `fcntl(F_GETPATH)` here, but the CF functions require CFURLs for paths and do not operate on fds. There does not seem to be a way to get the reclaimable space figures taking quotas into account (i.e. the difference between bfree and bavail). However there is AFAIK no supported way to enable quotas on macOS, so it strikes me as exceedingly unlikely that that would matter. I'm effectively setting CallerAvailableAllocationUnits and ActualAvailableAllocationUnits to the same value. -- https://gitlab.winehq.org/wine/wine/-/merge_requests/10014