Build PPAPI NaCl Glibc tests with GN

build/toolchain/nacl/BUILD.gn

 # Copyright (c) 2014 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("//build/config/sysroot.gni")
 import("//build/toolchain/nacl_toolchain.gni")
 
-nacl_toolchain_dir = rebase_path("//native_client/toolchain", root_build_dir)
-os_toolchain_dir = "${nacl_toolchain_dir}/${current_os}_x86"
+import("//build/config/nacl/nacl.gni")
 
 # Add the toolchain revision as a preprocessor define so that sources are
 # rebuilt when a toolchain is updated.
 # Idea we could use the toolchain deps feature, but currently that feature is
 # bugged and does not trigger a rebuild.
 # https://code.google.com/p/chromium/issues/detail?id=431880
 # Calls to get the toolchain revision are relatively slow, so do them all in a
 # single batch to amortize python startup, etc.
 revisions = exec_script("//native_client/build/get_toolchain_revision.py",
                         [
@@ skipping 180 matching lines @@
 
   # Some IRT implementations (notably, Chromium's) contain C++ code,
   # so we need to link w/ the C++ linker.
   ld = "${python_path} ${link_irt} --tls-edit=tls_edit --link-cmd=${cxx} --readelf-cmd=${readelf}"
 
   # TODO(ncbray): depend on link script
   deps = [
     "//native_client/src/tools/tls_edit:tls_edit($host_toolchain)",
   ]
 }