Use the extended library search path when looking for readline (simple
   oversight in using self.compiler.library_dirs)
diff --git a/setup.py b/setup.py
index a3a7c09..646dd43 100644
--- a/setup.py
+++ b/setup.py
@@ -173,7 +173,7 @@
             exts.append( Extension('rgbimg', ['rgbimgmodule.c']) )
 
         # readline
-        if (self.compiler.find_library_file(self.compiler.library_dirs, 'readline')):
+        if (self.compiler.find_library_file(lib_dirs, 'readline')):
             exts.append( Extension('readline', ['readline.c'],
                                    libraries=['readline', 'termcap']) )