net/tcpkali: fix build on FreeBSD 15

Our new inotify support confuses the bundled libev.
Unbundle libev to fix the build.
Something is fishy with this port; the upstream repository does not
exist anymore and the one listed in WWW is blank.
This should be investigated.

MFH: 2026Q1
(cherry picked from commit cfc41e9bfe637015f4710e0c745779dee738f478)