GN: Use build directory for CD for scripts

tools/gn/secondary/build/config/compiler/BUILD.gn

 # Copyright (c) 2013 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.
 
 # Base compiler configuration.
 config("compiler") {
   includes = [ "//" ]
   if (is_win) {
     cflags = [
       # TODO(brettw) these probably need to be refactored.
@@ skipping 72 matching lines @@
     }
 
     # Linux-specific compiler flags setup.
     # ------------------------------------
     if (is_linux) {
       cflags += [
         "-fPIC",
         "-pthread",
         "-pipe",  # Use pipes for communicating between sub-processes. Faster.
       ]
+      gold_path = to_build_path("//third_party/gold")
       ldflags += [
         # Use Gold for linking: it is checked out in the source tree.
-        "-B$relative_build_to_source_root_dir/third_party/gold",

[scottmg, 2013/09/14 04:53:16]

... hmm, i see that's more like what you had before :)

+        "-B$gold_path",
 
         "-fPIC",
         "-pthread",
         "-Wl,-z,noexecstack",
 
         # TODO(brettw) gold linker flags, only target.
         # There seems to be a conflict of --icf and -pie in gold which can
         # generate crashy binaries. As a security measure, -pie takes
         # precendence for now.
         # TODO(brettw) common.gypi has this only for target toolset.
@@ skipping 223 matching lines @@
 
         # Clang spots more unused functions.
         "-Wno-unused-function",
 
         # Warns when a const char[] is converted to bool.
         "-Wstring-conversion",
       ]
     }
   }
 }