Non-SFI mode: Use clone() instead of pthread_create()

src/untrusted/pthread/nc_thread.c

Index: src/untrusted/pthread/nc_thread.c
diff --git a/src/untrusted/pthread/nc_thread.c b/src/untrusted/pthread/nc_thread.c
index 8b0fe042179cc507530b26668fc4ba32b2b256be..7be3a7446335d260273759e7f3249aa44bb641c4 100644
--- a/src/untrusted/pthread/nc_thread.c
+++ b/src/untrusted/pthread/nc_thread.c
@@ -272,8 +272,6 @@ void __nc_initialize_globals(void) {
   __nc_thread_initialized = 1;
 }
 
-#if defined(NACL_IN_IRT)
-
 /*
  * This is used by the IRT for user threads.  We initialize all fields
  * so that we get predictable behaviour in case some IRT code does an
@@ -284,7 +282,7 @@ void __nc_initialize_unjoinable_thread(struct nc_combined_tdb *tdb) {
   tdb->tdb.joinable = 0;
 }
 
-#else
+#if !defined(NACL_IN_IRT)
 
 /*
  * Will be called from the library startup code,