zsh doesn't support standard "unalias -a"

[Martijn Dekker <martijn@xxxxxxxx>]

In a cross-platform shell library I'm writing, I would like to start by
removing all aliases from the current execution environment, to help
assure a consistent command language. The standard command to remove all
aliases is "unalias -a". See:
http://pubs.opengroup.org/onlinepubs/9699919799/utilities/unalias.html

(For instance, ksh93 unhelpfully aliases "command" to "command " by
default, causing additional alias expansion where I don't want it.)

Unfortunately it appears that zsh does not support the "-a" option to
unalias, so I have to resort to the proprietary zsh variant:

unalias -m '*'

It would be nice if the standard -a option were added (at least in POSIX
mode, if nothing else).

Thanks,

- Martijn