The current darshan-runtime configure script allows the caller to specify the zlib installation using the --with-zlib argument. Past versions of darshan required --with-zlib-for-mpi instead. If you accidentally paste an old configure command line from a previous release to use with darshan-runtime then it silently ignores the --with-zlib-for-mpi option.

We should probably have configure stop with an error if someone tries to use the old argument name.