Version 1.0.34 released.

• Fix a potential segmentation fault when connecting to an IPv6 peer via a proxy.
• Minor improvements to the build system.
• Make the systemd service file identical to the one from the 1.1 branch.
• Fix a potential problem causing IPv4 sockets to not work on macOS.

Thanks to Maximilian Stein and Wang Liu Shuai for their contributions to this version of tinc.