shells/ksh93: update to ksh 93u+m/1.0.8

# CHANGES (since 1.0.7)

  * Fixed a regression in the behaviour of exit in a trap action. The
    exit status used when no argument is given to exit is now once again
    the exit status of the last command executed before the trap action.

  * Fixed a race condition, introduced in 1.0.7, that occurred on some
    systems when running an external command with a standard output
    redirection from a command substitution.

  * Fixed an init-time crash on failure to trim the shell command
    history file due to a non-writeable parent directory; ksh now prints
    a warning instead.

  * The kill built-in command now correctly refuses to issue SIGSTOP to
    the shell's own process if the shell is a login shell.


(vins)