CURLOPT_EGDSOCKET(3) on macOS

The text fc2842f57871, 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 EGD socket path

CURLOPT_EGDSOCKET(3) on macOS now