MacOSX linker doesn't understand -R flag at all, no matter how you feed it
the flag.  Punt and return a -L flag instead (returning "" gums up the
command to be forked).
diff --git a/Lib/distutils/unixccompiler.py b/Lib/distutils/unixccompiler.py
index 831717b..692e3eb 100644
--- a/Lib/distutils/unixccompiler.py
+++ b/Lib/distutils/unixccompiler.py
@@ -196,7 +196,10 @@
         # the configuration data stored in the Python installation, so
         # we use this hack.
         compiler = os.path.basename(sysconfig.get_config_var("CC"))
-        if compiler == "gcc" or compiler == "g++":
+        if sys.platform[:6] == "darwin":
+            # MacOSX's linker doesn't understand the -R flag at all
+            return "-L" + dir
+        elif compiler == "gcc" or compiler == "g++":
             return "-Wl,-R" + dir
         else:
             return "-R" + dir