Override linkage in chicken-install

[Pietro Cerutti]

I figured I'd ask before coming along with a patch...

I have a use case where I boot up a CHICKEN environment, install a few 
eggs, compile a static application, then get rid of the environment 
altogether and just keep the application around. This happens inside 
FreeBSD jails where I want to keep only the bare mininum needed.

The CHICKEN environment is installed using binary packages, while the 
eggs - as you all know - are compiled on the fly.

Now, it would be great if I could specify to only compile static 
versions of the eggs, because that's what I'm going to use anyway.

If I built CHICKEN from source, that'd be STATICBUILD=1 (assuming the 
egg doesn't specify dynamic linkage only).

So, what do you guys think of allowing the linkage to be overridden by 
chicken-install? I guess I'd suggest a new option, -linkage, which can 
take the values 'static' and 'dynamic'. If the option is not provided, 
we do as we do today.

I can do the work, if you want the feature.

Thanks,


--
Pietro Cerutti
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