Add mention of PYTHONPATH if xcbgen cannot be found.

diff --git a/src/c_client.py b/src/c_client.py
index 7bcf5e7..835ae5c 100755 (executable)
--- a/src/c_client.py
+++ b/src/c_client.py
@@ -989,7 +989,8 @@ except ImportError:
     print ''
     print 'Failed to load the xcbgen Python package!'
     print 'Make sure that xcb/proto installed it on your Python path.'
-    print 'If not, you will need to create a .pth file to extend the path.'
+    print 'If not, you will need to create a .pth file or define $PYTHONPATH'
+    print 'to extend the path.'
     print 'Refer to the README file in xcb/proto for more info.'
     print ''
     raise