Change the command list to always include #shell and #suspend so that
a user's preferred key bindings can span platforms without worrying
about whether those exist or not. They're still effectively no-ops
when compiled out.
'#?' suppresses them from the list of displayed commands. Interface-
specific extended command handling may want to check new extcmd.flag
value CMD_NOT_AVAILABLE to do the same, but failing to do so shouldn't
pose a problem. They behave sanely if executed when not supported.
projects / nethack / commit