Fix set_name for vxworks. Length of name should be truncated to VX_TASK_RENAME_LENGTH-1

Author: biabbas

library/std/src/sys/pal/unix/thread.rs

@@ -222,16 +222,8 @@ impl Thread {
 
     #[cfg(target_os = "vxworks")]
     pub fn set_name(name: &CStr) {
-        // FIXME(libc): adding real STATUS, ERROR type eventually.
-        unsafe extern "C" {
-            fn taskNameSet(task_id: libc::TASK_ID, task_name: *mut libc::c_char) -> libc::c_int;
-        }
-
-        //  VX_TASK_NAME_LEN is 31 in VxWorks 7.
-        const VX_TASK_NAME_LEN: usize = 31;
-
-        let mut name = truncate_cstr::<{ VX_TASK_NAME_LEN }>(name);
-        let res = unsafe { taskNameSet(libc::taskIdSelf(), name.as_mut_ptr()) };
+        let mut name = truncate_cstr::<{ libc::VX_TASK_RENAME_LENGTH - 1 }>(name);
+        let res = unsafe { libc::taskNameSet(libc::taskIdSelf(), name.as_mut_ptr()) };
         debug_assert_eq!(res, libc::OK);
     }