Change startup ABI for untrusted code to be C-compatible

src/untrusted/nacl/pthread_initialize_minimal.c

 /*
  * Copyright (c) 2011 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include <unistd.h>
 
 #include "native_client/src/untrusted/nacl/nacl_irt.h"
 #include "native_client/src/untrusted/nacl/nacl_thread.h"
 #include "native_client/src/untrusted/nacl/tls.h"
 
 /*
  * This initialization happens early in startup with or without libpthread.
  * It must make it safe for vanilla newlib code to run.
  */
 int __pthread_initialize_minimal(size_t tdb_size) {
-  /*
-   * TODO(mcgrathr): This ought to be called by the startup code before
-   * this.  But there are too many variants of that code that would
-   * all need to be changed.
-   * See http://code.google.com/p/nativeclient/issues/detail?id=651
-   */
-  __libnacl_irt_init();
-
   /* Adapt size for sbrk. */
   /* TODO(robertm): this is somewhat arbitrary - re-examine). */
   size_t combined_size = (__nacl_tls_combined_size(tdb_size) + 15) & ~15;
 
   /*
    * Use sbrk not malloc here since the library is not initialized yet.
    */
   void *combined_area = sbrk(combined_size);
 
   /*
    * Fill in that memory with its initializer data.
    */
   void *tdb = __nacl_tls_initialize_memory(combined_area, tdb_size);
 
   /*
    * Set %gs, r9, or equivalent platform-specific mechanism.  Requires
    * a syscall since certain bitfields of these registers are trusted.
    */
   nacl_tls_init(tdb);
 
   /*
    * Initialize newlib's thread-specific pointer.
    */
   __newlib_thread_init();
 
   return 0;
 }