fix: define eventfd_t locally instead of re-export (cbindgen cross-module)

src/header/sys_eventfd/mod.rs

@@ -4,10 +4,13 @@ use crate::error::{Errno, ResultExt};
 use crate::header::fcntl::{O_CLOEXEC, O_NONBLOCK, O_RDWR};
 use crate::header::errno::EFAULT;
 use crate::header::errno::EINVAL;
-use crate::platform::{Pal, Sys, types::{c_int, c_uint}};
+use crate::platform::{Pal, Sys, types::{c_int, c_uint, uint64_t}};
 
-// Re-export eventfd_t from bits/eventfd.h
-pub use crate::header::bits_eventfd::eventfd_t;
+// cbindgen can't resolve re-exports across modules, so eventfd_t is
+// defined here directly (the C typedef lives in after_includes in
+// cbindgen.toml). bits_eventfd still has its own copy for independent
+// consumers that include only <bits/eventfd.h>.
+pub type eventfd_t = uint64_t;
 
 pub const EFD_SEMAPHORE: c_int = 1;
 pub const EFD_CLOEXEC: c_int = 0x80000;