add clock_nanosleep to freebsd 12 and netbsd

src/unix/bsd/freebsdlike/freebsd/freebsd12/mod.rs

@@ -221,6 +221,12 @@ extern "C" {
         msgtyp: ::c_long,
         msgflg: ::c_int,
     ) -> ::ssize_t;
+    pub fn clock_nanosleep(
+        clk_id: ::clockid_t,
+        flags: ::c_int,
+        rqtp: *const ::timespec,
+        rmtp: *mut ::timespec,
+    ) -> ::c_int;
 }
 
 cfg_if! {

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

@@ -1743,6 +1743,12 @@ safe_f! {
 extern "C" {
     pub fn ntp_adjtime(buf: *mut timex) -> ::c_int;
     pub fn ntp_gettime(buf: *mut ntptimeval) -> ::c_int;
+    pub fn clock_nanosleep(
+        clk_id: ::clockid_t,
+        flags: ::c_int,
+        rqtp: *const ::timespec,
+        rmtp: *mut ::timespec,
+    ) -> ::c_int;
 }
 
 #[link(name = "rt")]