CURLOPT_TIMEVALUE(3) on macOS

The text 60c851b2f0b5, as macOS 10.12.5, macOS 10.12.4, macOS 10.12.3, macOS 10.12.2, macOS 10.12.1, macOS 10.12 shipped it.

set time value for conditional

CURLOPT_TIMEVALUE(3) on macOS now