Sphinx: always exclude the build directory
We use the _build/ directory for all builders.
Some users may not have that directory excluded,
leading to some extra copy operations.
Fixes
@@ -178,3 +178,7 @@ if chinese:
latex_elements = latex_elements_user or latex_elements_rtd
elif japanese:
latex_engine = latex_engine_user or 'platex'
+
+# Make sure our build directory is always excluded
+exclude_patterns = globals().get('exclude_patterns', [])
+exclude_patterns.extend(['_build'])
