Auto merge of #2608 - devnexen:obsd_splice, r=Amanieu

openbsd adding splice struct for SO_SPLICE sock opt

Author: bors

libc-test/semver/openbsd.txt

@@ -1118,6 +1118,7 @@ siginfo_t
 sigwait
 sockaddr_dl
 sockpeercred
+splice
 srand
 stack_t
 statfs

src/unix/bsd/netbsdlike/openbsd/mod.rs

@@ -209,6 +209,12 @@ s! {
         pub sin_zero: [i8; 8],
     }
 
+    pub struct splice {
+        pub sp_fd: ::c_int,
+        pub sp_max: ::off_t,
+        pub sp_idle: ::timeval,
+    }
+
     pub struct kevent {
         pub ident: ::uintptr_t,
         pub filter: ::c_short,