https://gitlab.freedesktop.org/pipewire/pipewire-rs/-/merge_requests/209

Index: modcargo-crates/pipewire-0.7.2/src/channel.rs
--- modcargo-crates/pipewire-0.7.2/src/channel.rs.orig
+++ modcargo-crates/pipewire-0.7.2/src/channel.rs
@@ -232,6 +232,17 @@ where
         }
         unsafe { eventfd(0, 0x00100000) }
     };
+    #[cfg(target_os = "openbsd")]
+    let eventfd = {
+        // link to epoll-shim
+        #[link(name = "epoll-shim")]
+        use std::os::raw::{c_int, c_uint};
+        extern "C" {
+            pub fn eventfd(name: c_uint, flags: c_int) -> c_int;
+        }
+        const EFD_CLOEXEC :c_int = libc::O_CLOEXEC;
+        unsafe { eventfd(0, EFD_CLOEXEC) }
+    };
     if eventfd == -1 {
         panic!("Failed to create eventfd: {}", nix::errno::errno())
     }
