Unsetting a variable that was not previously set

[Vincent Lefevre <vincent@xxxxxxxxxx>]

zsh should return an exit status 0 when unsetting a variable that was
not previously set.

greux:~> zsh-beta -f
greux% echo $ZSH_VERSION
4.1.0-dev-7
greux% unset blah && echo OK
greux%

It should have printed 'OK'.

See
  http://www.opengroup.org/onlinepubs/007904975/utilities/unset.html

"Unsetting a variable or function that was not previously set shall
not be considered an error and does not cause the shell to abort."

The following shells print 'OK' as expected:
  * /bin/sh under Solaris
  * /bin/sh under OSF1
  * bash (under Linux)

-- 
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.org/> - 100%
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Work: CR INRIA - computer arithmetic / SPACES project at LORIA