netbsd adding _lwp_park api.

(backport <#3721>)
(cherry picked from commit 4769aaa)

Author: devnexen

libc-test/semver/netbsd.txt

@@ -1190,6 +1190,9 @@ _cpuset_destroy
 _cpuset_isset
 _cpuset_set
 _cpuset_zero
+_lwp_park
+_lwp_unpark
+_lwp_unpark_all
 _lwp_self
 abs
 accept4

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

@@ -2875,6 +2875,22 @@ extern "C" {
     pub fn getrandom(buf: *mut ::c_void, buflen: ::size_t, flags: ::c_uint) -> ::ssize_t;
 
     pub fn reboot(mode: ::c_int, bootstr: *mut ::c_char) -> ::c_int;
+
+    #[link_name = "___lwp_park60"]
+    pub fn _lwp_park(
+        clock: ::clockid_t,
+        flags: ::c_int,
+        ts: *const ::timespec,
+        unpark: ::lwpid_t,
+        hint: *const ::c_void,
+        unparkhint: *mut ::c_void,
+    ) -> ::c_int;
+    pub fn _lwp_unpark(lwp: ::lwpid_t, hint: *const ::c_void) -> ::c_int;
+    pub fn _lwp_unpark_all(
+        targets: *const ::lwpid_t,
+        ntargets: ::size_t,
+        hint: *const ::c_void,
+    ) -> ::c_int;
 }
 
 #[link(name = "rt")]