Added arguments to NaCl scons to allow custom toolchain directories.

tests/gdb/nacl.scons

Index: tests/gdb/nacl.scons
diff --git a/tests/gdb/nacl.scons b/tests/gdb/nacl.scons
index 78120a0f930dcef1f161e061b888906f519464c2..790598ca6b9fe157df11d1f0fdbc7d14a982e7f1 100644
--- a/tests/gdb/nacl.scons
+++ b/tests/gdb/nacl.scons
@@ -18,15 +18,9 @@ if env.Bit('target_arm') or env.Bit('target_mips32'):
     # 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: