Bug#948919: sambamba - htslib needs patch - guix - has the answer

[Steffen Möller]

http://git.genenetwork.org/guix-bioinformatics/guix-bioinformatics/src/commit/a2a200402b91a352dbdede01eec85accb892b8e1/htslib-add-cram_to_bam.patch

That patch just makes the cram_to_bam routine visible and should be
adopted without danger.

Steffen