Add a way to make htslib use additional libraries
Add a way to make htslib use additional libraries

ekg/vcflib,vcflib/vcflib,ekg/vcflib,ekg/vcflib,ekg/vcflib,vcflib/vcflib,vcflib/vcflib,vcflib/vcflib,vcflib/vcflib,ekg/vcflib,vcflib/vcflib,vcflib/vcflib,vcflib/vcflib