sippy/rtpproxy ? reverse-engineered prompt

I want this repo to build cleanly on a modern Linux machine and give me a working RTP proxy service I can run locally.

Please make sure it compiles from source with the included submodules, and that the main build and install flow is straightforward. I also want a simple way to start it, configure a listening control channel, and verify that it can relay RTP traffic for SIP calls the way the README describes.

If there are missing pieces for a fresh setup, please add whatever is needed so someone can clone the repo, build it, run a basic test, and understand how to use it with a SIP proxy like Kamailio or OpenSIPS. Keep the existing behavior intact, and if you need to check current docs or dependencies online, do that too.