hdf5_ep

[svn-r8480] Purpose: bug fix

Description: Solaris 64-bit machines cannot handle round-up correctly during
conversion between unsigned (long) long and double.

Solution: During configuration, run a program to test if there is any failure
during conversion.  Enable a macro if failures happen and adjust the test/dtypes
for round-up.

Platforms tested: h5committest, arabica 64-bit.