Restore tools/ld_bfd/ld that drover didn't bring back

tools/ld_bfd/ld

+#!/usr/bin/python
+# Copyright (c) 2011 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.
+
+"""Wrapper for invoking the BFD loader
+
+A simple script to invoke the bfd loader instead of gold.
+This script is in a filename "ld" so it can be invoked from gcc
+via the -B flag.
+"""
+# TODO(bradchen): Delete this script when Gold supports linker scripts properly.
+import os
+import subprocess
+import sys
+
+def PathTo(fname):
+  if fname[0] == os.pathsep:
+    return fname
+  for p in os.environ["PATH"].split(os.pathsep):
+    fpath = os.path.join(p, fname)
+    if os.path.exists(fpath):
+      return fpath
+  return fname
+
+def FindLDBFD():
+  cxx = os.getenv("CXX")
+  if not cxx:
+    cxx = "g++"
+  popen = subprocess.Popen(cxx + " -print-prog-name=ld",
+                           shell=True,
+                           stdout=subprocess.PIPE,
+                           stdin=subprocess.PIPE)
+  (ld, error) = popen.communicate()
+  if popen.wait() != 0:
+    print "Could not find ld:" + error
+    return "ld"
+  ld = ld.strip()
+  ld_bfd = PathTo(ld + ".bfd")
+  if os.access(ld_bfd, os.X_OK):
+    return ld_bfd
+  return ld
+
+def main():
+  args = [FindLDBFD()] + sys.argv[1:]
+  print("tools/ld_bfd/ld: exec " + ' '.join(args))
+  sys.exit(subprocess.call(args))
+
+if __name__ == "__main__":
+  main()