diff -Naur a/clang/docs/conf.py b/clang/docs/conf.py
--- a/clang/docs/conf.py	2020-09-15 09:12:24.318287611 +0000
+++ b/clang/docs/conf.py	2020-09-15 15:01:00.025893199 +0000
@@ -37,21 +37,7 @@
     ".rst": "restructuredtext",
 }
 
-try:
-    import recommonmark
-except ImportError:
-    # manpages do not use any .md sources
-    if not tags.has("builder-man"):
-        raise
-else:
-    import sphinx
-
-    if sphinx.version_info >= (3, 0):
-        # This requires 0.5 or later.
-        extensions.append("recommonmark")
-    else:
-        source_parsers = {".md": "recommonmark.parser.CommonMarkParser"}
-    source_suffix[".md"] = "markdown"
+import sphinx
 
 # The encoding of source files.
 # source_encoding = 'utf-8-sig'