Modify ARM .S code so it can be processed by both gnu-as and llvm-mc.

src/untrusted/irt/aeabi_read_tp.S

 /*
  * 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 "native_client/src/trusted/service_runtime/nacl_config.h"
 
 /*
  * The IRT uses its own private TLS, leaving r9 for the application.
  * We must define __aeabi_read_tp to get the private one instead of
  * the standard one.  The EABI requires that this function preserve
  * all registers except r0 (the return value register).  A normal
  * function is permitted to clobber r1, r2, and r3 as well, so we
  * cannot define this in C.
  */
 
         .globl __aeabi_read_tp
         .type __aeabi_read_tp,%function
         .p2align NACL_BLOCK_SHIFT
 __aeabi_read_tp:
         push {r1, r2, r3, lr}
-
-        /*
-         * Insert enough nops so the call is the last instruction in the bundle.
+        nop
+        nop
+        /* NOTE: The call must be last slot in the bundle.
+         *       Consider using the pnacl specifc pseudo opcodes
+         *       once we build this with llvm-mc only.
          */
-        .rept ((NACL_BLOCK_SIZE - (. - __aeabi_read_tp)) / 4) - 1
-        nop
-        .endr
         bl __nacl_read_tp
 
         pop {r1, r2, r3, lr}
         bic lr, lr, #NACL_CONTROL_FLOW_MASK
         bx lr