In _pthread_key_create() ensure that libthr is initialized. This

fixes a NULL-dereference of curthread when libstdc+ initializes
the exception handling globals on archs we can't use GNU TLS due
to lack of support in binutils 2.15 (i.e. arm and sparc64), yet,
thus making threaded C++ programs compiled with GCC 4.2.1 work
again on these archs.

Reviewed by:	davidxu
MFC after:	3 days

lib/libthr/thread/thr_spec.c

@@ -51,9 +51,13 @@ __weak_reference(_pthread_setspecific, pthread_setspecific);
 int
 _pthread_key_create(pthread_key_t *key, void (*destructor) (void *))
 {
-	struct pthread *curthread = _get_curthread();
+	struct pthread *curthread;
 	int i;
 
+	_thr_check_init();
+
+	curthread = _get_curthread();
+
 	/* Lock the key table: */
 	THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
 	for (i = 0; i < PTHREAD_KEYS_MAX; i++) {