hdf5: added comments for the existing configure options

develop/hdf5/hdf5.conf

@@ -15,10 +15,14 @@
 # GNU General Public License can be found in the file COPYING.
 # --- SDE-COPYRIGHT-NOTE-END ---
 
+# Compile the C++ interface [default=no]
 var_append extraconfopt ' ' "--enable-cxx"
+# Enable thread safe capability
 var_append extraconfopt ' ' "--enable-threadsafe"
-var_append extraconfopt ' ' "--enable-gpfs"
+# Use the Pthreads library [default=no]
 var_append extraconfopt ' ' "--with-pthread"
+# Enable GPFS hints for the MPI/POSIX file driver [default=no]
+var_append extraconfopt ' ' "--enable-gpfs"
 
 # TODO:
 # -config option for enable-cxx