Index: setup.py
===================================================================
--- setup.py	(revision 68142)
+++ setup.py	(working copy)
@@ -1588,7 +1600,7 @@
 
         # If Cygwin, then verify that X is installed before proceeding
         if platform == 'cygwin':
-            x11_inc = find_file('X11/Xlib.h', [], include_dirs)
+            x11_inc = find_file('X11/Xlib.h', ['/usr/include'], include_dirs)
             if x11_inc is None:
                 return