[PATCH] init-if-undefined command

[Andrew STUBBS]

Andrew Stubbs wrote:
> The attached patch adds a new CLI command named 'init-if-undefined'.
> 
> This is essentially the same a 'set variable' (for convenience variables 
> only), but does not set the variable if it already has a value.
> 
> It is useful in scripts whose values can be overridden, or as an 
> approximation of a statically initialised variable.

Here's another one that ought to be easy to approve/reject.

The docs have been approved and we have decided that this should be 
mentioned in the NEWS if/when it goes in, but nobody has said anything 
about the code.

I don't think this one should be too much trouble because it does not 
change existing behaviour or do much out of keeping with other commands.

Is it OK?

Thanks

Andrew Stubbs