Use gcc-mp-4.4 to build TSan on Mac....

scripts/macports-gcc-wrapper/wrapper.py

+#!/usr/bin/python
+
+# Copyright (c) 2010 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 os
+import subprocess
+import sys
+
+# This python script wraps gcc-mp-4.X so it can handle
+# compilation options memcheck uses on Mac, including:
+#  a) skip "-arch XXX"
+#  b) define empty "__private_extern__" macro so it doesn't bark
+#     on mac-specific code using this keyword.
+#  c) skip "-mno-dynamic-no-pic" and "-mdynamic-no-pic"
+#     This may not be a very clean solution in general but it works.
+
+# The gcc command should be passes as an environment variable,
+# e.g. GCC_BINARY_MASK=/opt/local/bin/XXX-mp-4.4
+assert os.environ.has_key("GCC_BINARY_MASK")
+gcc_binary_mask = os.environ["GCC_BINARY_MASK"]
+gcc = gcc_binary_mask.replace("XXX", sys.argv[1])
+
+gcc_command = [gcc, "-D__private_extern__="]
+skip = 0
+for arg in sys.argv[2:]:
+  if skip > 0:
+    skip -= 1
+    continue
+  if arg == "-arch":
+    skip = 1
+    continue
+  if arg == "-mno-dynamic-no-pic":
+    continue
+  if arg == "-mdynamic-no-pic":
+    continue
+  gcc_command.append(arg)
+
+subprocess.call(gcc_command)