Document that --build disables cleanups
@@ -441,6 +441,7 @@ build_dir = partial(
'an initial build still takes place in a temporary directory. '
'The location of temporary directories can be controlled by setting '
'the TMPDIR environment variable (TEMP on Windows) appropriately. '
+ 'When passed, build directories are not cleaned in case of failures.'
) # type: Any
ignore_requires_python = partial(
