hdf5doc

Purpose:
Bug fix

Description:
modi4 dies during build with strange errors.
The root cause of these is a two-year-old hack in HDF5's libtool
script that only takes effect on IRIX.

Solution:
Edited the libtool hack (by editing ltmain.sh) to correct a bug in
the hack.
Also made sure that compiler-specific DEFAULT_LIBS are used
when linking.

Platforms tested:
sleipnir, copper, modi4, sol