SUBSHELL option (and usability) do not work for my ordinary users with /bin/sh login shell, either option chosen or not during port build process. This behaviour was noted for ages. And I even used to it. For my root (with csh login shel) SUBSHELL worked fine (and I use it).
But from previous (or last) upgrade, misc/mc if built with chosen SUBSHELL option do not even start for users with /bin/sh as default login shells.
common.c: unimplemented subshell type 1
read (subshell_pty...): No error: 0 (0)
I have reported this problem to the upstream mc project team here:
This is a longstanding bug. I would suggest that the subshell build option be disabled by default or that, at the very least, an informational message be emitted that a user either needs to use the -u option to start or that the user's default shell should be changed, if a different shell will cause it to work.