Added arguments to NaCl scons to allow custom toolchain directories.

tests/gdb/nacl.scons

 # -*- python -*-
 # Copyright (c) 2012 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.
 
 import os
 
 Import('env')
 
 if 'TRUSTED_ENV' not in env:
   Return()
 
 if env.UnderWindowsCoverage():
   Return()
 
 if env.Bit('target_arm') or env.Bit('target_mips32'):
   if env.UsingEmulator():
     # nacl-gdb is built with ARM support but not MIPS support.
     if env.Bit('target_mips32'):
       Return()
-    platform_build_dir = env.GetPlatformBuildTargetDir()
-    toolchain_name = env.GetToolchainName(target_arch='x86',
-                                          is_pnacl=False,
-                                          lib_name='newlib')
-
-    nacl_x86_toolchain_dir = env.GetToolchainDir(
-        platform_build_dir=platform_build_dir,
-        toolchain_name=toolchain_name
-    )
+    nacl_x86_toolchain_dir = env.GetToolchainDir(target_arch='x86',
+                                                 is_pnacl=False,
+                                                 lib_name='newlib')
     nacl_gdb_path = os.path.join(nacl_x86_toolchain_dir, 'bin', 'i686-nacl-gdb')
     env.Replace(GDB=nacl_gdb_path)
   else:
     # Use the system's ARM/MIPS GDB because the NaCl toolchain does not
     # include a copy of GDB built to run on ARM/MIPS.
     env.Replace(GDB='gdb')
     # Unlike nacl-gdb, the system version of GDB does not support the
     # "nacl-irt" command.
     if env.Bit('tests_use_irt'):
       Return()
@@ skipping 122 matching lines @@
 # work on qemu-arm.
 AddGdbTest('break_continue_thread', is_thread_test=True,
            is_broken=env.UsingEmulator())
 
 AddGdbTest('syscall_thread', is_thread_test=True)
 
 # We don't run this test on non-x86 architectures or PNaCl since it
 # contains inline assembly.
 if env.Bit('target_x86') and not env.Bit('bitcode'):
   AddGdbTest('mmap')