CURLOPT_MAXCONNECTS(3) on macOS

The text a1c90358590c, 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.

maximum connection cache size

CURLOPT_MAXCONNECTS(3) on macOS now