CURLOPT_STREAM_DEPENDS_E(3) on macOS

The text 562502a25315, 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 execlusively

CURLOPT_STREAM_DEPENDS_E(3) on macOS now