MacOS – PPTP VPN client for macOS Sierra or iOS 10

Apple has removed PPTP VPN support in Sierra due to security concerns. See: https://support.apple.com/en-us/HT206844

Unfortunately, I need to connect to an organisation that only supports PPTP (not my decision).

I know about Shimo, but it's $50 and has a lot of features I don't need.

I was hoping to find a free or open source solution? A command-line-only option would be fine for macOS.

I'm even open to more esoteric solutions (e.g. a lightweight linux VM that connects to the VPN, and then shares the connection with host OS, but not sure how feasible this would be or how to do it).

Edit: I see the command-line tool pppd is still present in macOS Sierra, so perhaps it's possible to call this directly?

Edit 2: I tried following this tutorial with an options file from the ArchWiki, and a custom route in /etc/ppp/ip-up, but it gives an error (publish_entry SCDSet() failed: Success!) when I try to run the pppd command, the pppd daemon doesn't seem to be running, and the ppp0 interface isn't showing up in ifconfig. I don't know much about networks and network interfaces, so I'm finding this very confusing! Any help would be much appreciated.