std::thread: adding get_name haiku implementation.

follow-up #123233

Author: devnexen

Diff for: library/std/src/sys/pal/unix/thread.rs

@@ -257,14 +257,31 @@ impl Thread {
         CString::new(name).ok()
     }
 
+    #[cfg(target_os = "haiku")]
+    pub fn get_name() -> Option<CString> {
+        let mut name = vec![0u8; libc::B_OS_NAMELENGTH];
+        unsafe {
+            let mut tinfo = mem::MaybeUninit::<libc::thread_info>::uninit();
+            let thread_self = libc::find_thread(ptr::null_mut());
+            let res = libc::get_thread_info(thread_self, tinfo.as_mut_ptr());
+            if res != libc::B_OK {
+                return None;
+            }
+            let info = tinfo.assume_init();
+            name = info.name.iter().map(|&c| c as u8).collect();
+            CString::new(name).ok()
+        }
+    }
+
     #[cfg(not(any(
         target_os = "linux",
         target_os = "freebsd",
         target_os = "netbsd",
         target_os = "macos",
         target_os = "ios",
         target_os = "tvos",
-        target_os = "watchos"
+        target_os = "watchos",
+        target_os = "haiku"
     )))]
     pub fn get_name() -> Option<CString> {
         None