With the change from SRFI 174 to SRFI 19, set-file-times takes a couple of the latter's time objects, which are created with its make-time. Which requires a time-type as its first argument; we're currently using time-monotonic and time-utc in SRFI 170 for the posix-time and monotonic-time procedures that get the current time.We should probably either specify that the time-type is ignored by set-file-times, or perhaps specify "it is an error" if it isn't time-utc.
I'm also creating time-utc time objects for file-info's (stat's) file-info:a/m/ctime fields, perhaps that should also be specified instead of assumed.