Merge branch 'pkey-del' into 'master'

Fix EINVAL at pthread_key_delete

See merge request redox-os/relibc!1304

src/header/pthread/tls.rs

@@ -82,11 +82,15 @@ pub unsafe extern "C" fn pthread_key_create(
 
 #[unsafe(no_mangle)]
 pub unsafe extern "C" fn pthread_key_delete(key: pthread_key_t) -> c_int {
-    if KEYS.lock().remove(&key).is_none() || VALUES.borrow_mut().remove(&key).is_none() {
+    if KEYS.lock().remove(&key).is_none() {
         // We don't have to return anything, but it's not less expensive to ignore it.
         return EINVAL;
     }
 
+    // POSIX recommends to return EINVAL if the value does not "refers"
+    // to this key, but we do not map VALUES back to KEYS
+    VALUES.borrow_mut().remove(&key);
+
     0
 }