sys-libs/zlib

bzip2?
      ( app-arch/bzip2:= )

lzma?
      ( app-arch/xz-utils )

ssl?
      ( gnutls?
            ( dev-libs/nettle:0= >=net-libs/gnutls-3.6.5:= )
       !gnutls?
            ( mbedtls?
                  ( net-libs/mbedtls:= )
             !mbedtls?
                  ( dev-libs/openssl:0= )
             )
       )

zstd?
      ( app-arch/zstd )