adding a handful of linux fanotify data types.

close rust-lang#3688

(backport <rust-lang#3695>)
(cherry picked from commit 7b338f9)

Author: devnexen

src/unix/linux_like/linux/gnu/mod.rs

@@ -427,6 +427,17 @@ s! {
         pub tcpi_rcv_space: u32,
         pub tcpi_total_retrans: u32,
     }
+
+    pub struct fanotify_event_info_pidfd {
+        pub hdr: ::fanotify_event_info_header,
+        pub pidfd: ::__s32,
+    }
+
+    pub struct fanotify_event_info_error {
+        pub hdr: ::fanotify_event_info_header,
+        pub error: ::__s32,
+        pub error_count: ::__u32,
+    }
 }
 
 impl siginfo_t {