fix duplicate option in Sphinx config

docs/conf.py

@@ -62,8 +62,6 @@ source_suffix = '.rst'
 # The master toctree document.
 master_doc = 'index'
 
-exclude_patterns = ['py*', 'build']
-
 # General information about the project.
 project = 'Cython'
 authors = 'Stefan Behnel, Robert Bradshaw, Dag Sverre Seljebotn, Greg Ewing, William Stein, Gabriel Gellner, et al.'
@@ -102,7 +100,7 @@ today_fmt = '%B %d, %Y'
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
-exclude_patterns = []
+exclude_patterns = ['py*', 'build', 'BUILD']
 
 # The reST default role (used for this markup: `text`) to use for all documents.
 #default_role = None