Add struct sock_txtime and related flags

These are needed to use the SO_TXTIME socket option on Linux, which is
already exposed.

Author: ghedo

libc-test/semver/linux.txt

@@ -2020,6 +2020,8 @@ SOF_TIMESTAMPING_SOFTWARE
 SOF_TIMESTAMPING_SYS_HARDWARE
 SOF_TIMESTAMPING_TX_HARDWARE
 SOF_TIMESTAMPING_TX_SOFTWARE
+SOF_TXTIME_DEADLINE_MODE
+SOF_TXTIME_REPORT_ERRORS
 SOL_AAL
 SOL_ALG
 SOL_ATM
@@ -2996,6 +2998,7 @@ sigwaitinfo
 sock_extended_err
 sock_filter
 sock_fprog
+sock_txtime
 sockaddr_alg
 sockaddr_can
 sockaddr_ll

src/unix/linux_like/linux/mod.rs

@@ -581,6 +581,13 @@ s! {
         pub nla_len: u16,
         pub nla_type: u16,
     }
+
+    // linux/net_tstamp.h
+    #[cfg(not(all(target_env = "musl", target_arch = "mips")))]
+    pub struct sock_txtime {
+        pub clockid: ::clockid_t,
+        pub flags: ::__u32,
+    }
 }
 
 s_no_extra_traits! {
@@ -2528,6 +2535,10 @@ pub const SOF_TIMESTAMPING_RX_SOFTWARE: ::c_uint = 1 << 3;
 pub const SOF_TIMESTAMPING_SOFTWARE: ::c_uint = 1 << 4;
 pub const SOF_TIMESTAMPING_SYS_HARDWARE: ::c_uint = 1 << 5;
 pub const SOF_TIMESTAMPING_RAW_HARDWARE: ::c_uint = 1 << 6;
+#[cfg(not(all(target_env = "musl", target_arch = "mips")))]
+pub const SOF_TXTIME_DEADLINE_MODE: u32 = 1 << 0;
+#[cfg(not(all(target_env = "musl", target_arch = "mips")))]
+pub const SOF_TXTIME_REPORT_ERRORS: u32 = 1 << 1;
 
 // linux/if_alg.h
 pub const ALG_SET_KEY: ::c_int = 1;