Dear Guix,

I want to add another R package: VariantAnnotation.  For this I also had
to add another R package called "zlibbioc".

Even though we provide zlib in GNU Guix, and it also uses the zlib input
instead of zlib provided by this package, it is a required dependency of
VariantAnnotation.  Instead of customizing the VariantAnnotation package
(and deviate from upstream development), I believe this is a fairly nice
solution.

I hope this is fine with you.

Kind regards,
Roel Janssen