Tobias Berner authored May 31, 2020 and Adriaan de Groot committed Jun 05, 2020

- On FreeBSD epoll.h if provided through a library (from a port, epoll-shim)
  that emulates the Linux behavior. Make a CMake module for it to hide
  differences in systems behind a module.
- Find epoll on FreeBSD and link to it

Now on FreeBSD, tries to compile virtual_terminal.cpp, which will fail because
that needs more patches.