CURLOPT_STREAM_DEPENDS(3) on macOS

The text 393b7734d85f, 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 stream this transfer depends on

CURLOPT_STREAM_DEPENDS(3) on macOS now