fixes) where a variable containing a CTL char (the only possibility used
to be CTLESC (0x81)) would lose that character if the variable was expanded
when "set -f" (noglob) was in effect.
1.128 made this worse by adding more 0x8z values (a couple more) which would
see the same behaviour, and one of those was noticed by Martijn Dekker.
The reasoning was that when noglob is on, when a var is expanded, there are
no magic chars, so (apparently) no need to escape anything. Hence nothing
was escaped .. including any CTL chars that happened to be present. When
we later rmescapes() the CTL chars that we expect might occur are summarily
removed - even if they weren't really CTL chars, but just data masquerading.
We must *always* escape any CTL char clones that are in the var value,
no matter what other conditions apply, and what we expect to happen next.
While here, fix rmescapes() (and its $(()) clone, rmescapes_nl()) to
be more robust, less likely to forget to delete anything (which was
not the issue here, just the reverse) and in a DEBUG shell, have the
shell abort() if it encounters something in rmescapes() it is not
anticipating, so the code can be made to handle it, or if it should
not happen, we can find out why it did.
XXX pullup -8 (but will need to be via patch, code is quite different).
58e34de6bb