-# There is an easier implementation which provides the full date·time by archiving an empty file and then reading it back out of the archive :—
-#
-# $(shell LC_TIME=POSIX TZ=UTC0 $(TOUCH) -m -r $(callquote,$1) $(BUILDDIR)/.mtime && $(PAX) -w -x ustar $(BUILDDIR)/.mtime | $(PAX) -v -o 'listopt=%(mtime=%Y-%m-%dT%H:%M:%SZ)T')
-#
-# However, it depends on the `listopt´ option in `pax´, which (despite being specified in Posix) no implementations actually support.