- Get the package closer to what upstream intended:
  - Do not move the headers into a subfolder of /usr/include
  - Make a libev-libevent-devel subpackage to contain the libevent
    compatibility header, so that only this subpackage conflicts with
    libevent-devel, not all of libev-devel
  - Drop the pkgconfig file, as upstream rejected it several times already.