Reduce absolute paths in generated ninja files

ppapi/native_client/nacl_test_data.gni

 # Copyright 2015 The Chromium 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/nacl/rules.gni")
 
 assert(enable_nacl)
 
 if (current_cpu == "pnacl") {
   if (is_nacl_nonsfi) {
@@ skipping 233 matching lines @@
         }
 
         args = [
           "pnacl-translate",
           rebase_path(pexe, root_build_dir),
           "-o",
           rebase_path(nexe, root_build_dir),
           "-arch",
           arch,
           "-Wl,-L" +
-              rebase_path(get_label_info(pnacl_irt_shim, "target_out_dir")),
+              rebase_path(get_label_info(pnacl_irt_shim, "target_out_dir"),
+                          root_build_dir),
         ]
         deps = [
           ":$nexe_target_name(//build/toolchain/nacl:newlib_pnacl)",
         ]
         data_deps = [
           pnacl_irt_shim,
         ]
       }
     }
 
@@ skipping 125 matching lines @@
       }
     }
     if (generate_nmf) {
       data_deps += [ ":$nmf_target_name" ]
     }
     if (defined(invoker.test_files)) {
       data_deps += [ ":$test_files_target_name" ]
     }
   }
 }