When compiling bzip2/zlib from source, should they be compiled with global visibility?

Hi, as of Boost 1.69 on non-windows systems the default visibility is set to hidden. When requesting boost to build bzip2/zlib from source, it causes libboost_bzip2.so and libboost_zlib.so shared lib symbols to be built with hidden visibility, then they cannot be linked to libboost_iostreams.so

```
.../libboost_iostreams.so: undefined reference to `BZ2_bzCompressEnd'
.../libboost_iostreams.so: undefined reference to `BZ2_bzDecompressEnd'
.../libboost_iostreams.so: undefined reference to `BZ2_bzCompressInit'
.../libboost_iostreams.so: undefined reference to `BZ2_bzDecompress'
.../libboost_iostreams.so: undefined reference to `BZ2_bzDecompressInit'
.../libboost_iostreams.so: undefined reference to `BZ2_bzCompress'
```

Is there any workaround for this besides building all of boost with global visibility? or building bzip2/zlib externally? Can I patch the Jamfile or rebuild just bzip2/zlip/iostreams with global visibility?