Make the main thread detached.

Author: Vytautas Astrauskas

src/thread.rs

@@ -177,7 +177,9 @@ impl<'mir, 'tcx> Default for ThreadManager<'mir, 'tcx> {
     fn default() -> Self {
         let mut threads = IndexVec::new();
         // Create the main thread and add it to the list of threads.
-        threads.push(Default::default());
+        let mut main_thread = Thread::default();
+        main_thread.join_status = ThreadJoinStatus::Detached;
+        threads.push(main_thread);
         Self {
             active_thread: ThreadId::new(0),
             threads: threads,

tests/compile-fail/concurrency/libc_pthread_join_self.rs

@@ -6,11 +6,15 @@
 
 extern crate libc;
 
-use std::ptr;
+use std::{ptr, thread};
 
 fn main() {
-    unsafe {
-        let native: libc::pthread_t = libc::pthread_self();
-        assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0); //~ ERROR: Undefined Behavior: trying to join itself
-    }
+    let handle = thread::spawn(|| {
+        unsafe {
+            let native: libc::pthread_t = libc::pthread_self();
+            assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0); //~ ERROR: Undefined Behavior: trying to join itself
+        }
+    });
+    thread::yield_now();
+    handle.join().unwrap();
 }