Add -mtls-use-call option to avoid %gs:0 TLS accesses.

gcc/config.gcc

 # GCC target-specific configuration file.
 # Copyright 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
 # 2008, 2009 Free Software Foundation, Inc.
 
 #This file is part of GCC.
 
 #GCC is free software; you can redistribute it and/or modify it under
 #the terms of the GNU General Public License as published by the Free
 #Software Foundation; either version 3, or (at your option) any later
 #version.
@@ skipping 1065 matching lines @@
         tm_file="${tm_file} openbsd.h i386/openbsdelf.h"
         gas=yes
         gnu_ld=yes
         ;;
 i[34567]86-*-coff*)
         tm_file="${tm_file} i386/unix.h i386/bsd.h i386/gas.h dbxcoff.h i386/i386-coff.h"
         ;;
 *-*-nacl*)
         tm_file="${tm_file} i386/unix.h i386/att.h dbxelf.h elfos.h svr4.h i386/nacl.h"
         tmake_file="${tmake_file} i386/t-crtstuff i386/t-crtpc i386/t-crtfm t-dfprules i386/t-nacl64"
+        extra_options="${extra_options} i386/nacl.opt"
         ;;
 i[34567]86-*-linux* | i[34567]86-*-kfreebsd*-gnu | i[34567]86-*-knetbsd*-gnu | i[34567]86-*-gnu* | i[34567]86-*-kopensolaris*-gnu)
                         # Intel 80386's running GNU/*
                         # with ELF format using glibc 2
         tm_file="${tm_file} i386/unix.h i386/att.h dbxelf.h elfos.h svr4.h linux.h"
         case ${target} in
         i[34567]86-*-linux*)
                 if test x$enable_targets = xall; then
                         tm_file="${tm_file} i386/x86-64.h i386/linux64.h"
                         tm_defines="${tm_defines} TARGET_BI_ARCH=1"
@@ skipping 2086 matching lines @@
 
 if test "$target_cpu_default2" != ""
 then
         if test "$target_cpu_default" != ""
         then
                 target_cpu_default="(${target_cpu_default}|${target_cpu_default2})"
         else
                 target_cpu_default=$target_cpu_default2
         fi
 fi