mc: fix build failure

fix a build error with new mc 4.8.11 by adopting upstream fix
build error:
https://www.midnight-commander.org/ticket/3144
fixed upstream:
https://www.midnight-commander.org/changeset/d870aedad1907773f8586fe818a89e6b5178b849

Signed-off-by: Dirk Neukirchen <dirkneukirchen@web.de>