The code in 0.9rc2 seems to assume api version 1.6 for HDF5, but the default for HDF5 is now version 1.8. Which breaks the make.
This can be fixed by compiling HDF5 with 1.6 default, but a small patch in GDL seems a better solution.
Without being an expert in either, putting the line
#define H5_USE_16_API 1
before the include in hdf5_fun.hpp seems to do the trick.
2009-03-10 20:09:46 UTC in GDL - GNU Data Language