Rollup merge of #112352 - dankm:fbsd_doc_fix, r=thomcc

Fix documentation build on FreeBSD

After the socket ancillary data implementation was introduced, the documentation build was broken on FreeBSD hosts, add the same workaround as for the existing implementations.

Fixes the doc build after #91793

Author: matthiaskrgr

std/src/os/unix/net/ancillary.rs

@@ -11,7 +11,13 @@ use crate::slice::from_raw_parts;
 use crate::sys::net::Socket;
 
 // FIXME(#43348): Make libc adapt #[doc(cfg(...))] so we don't need these fake definitions here?
-#[cfg(all(doc, not(target_os = "linux"), not(target_os = "android"), not(target_os = "netbsd")))]
+#[cfg(all(
+    doc,
+    not(target_os = "linux"),
+    not(target_os = "android"),
+    not(target_os = "netbsd"),
+    not(target_os = "freebsd")
+))]
 #[allow(non_camel_case_types)]
 mod libc {
     pub use libc::c_int;