Fix docs build.

Author: carljm

Doc/library/compileall.rst

@@ -110,9 +110,9 @@ There is no command-line option to control the optimization level used by the
 provides the option: :program:`python -O -m compileall`.
 
 Similarly, the :func:`compile` function respects the :attr:`sys.bytecode_prefix`
-setting (via :envvar:`PYTHONBYTECODEPREFIX` or :opt:`-X` ``bytecode_prefix``).
-The generated bytecode cache will only be useful if :func:`compile` is run with
-the same :attr:`sys.bytecode_prefix` (if any) that will be used at runtime.
+setting. The generated bytecode cache will only be useful if :func:`compile` is
+run with the same :attr:`sys.bytecode_prefix` (if any) that will be used at
+runtime.
 
 Public functions
 ----------------