hdf5_ep

[svn-r11087] Purpose: Bug fix.

Description: When converting floating-point numbers to integers and the values of
floating-point number are greater than the maximal value of integer, Cray X1 generates
floating exception.

Solution: Added a test in configure to detect Cray X1's exception.  Set a flag to
indicate the machine that can handle overflow converting all floating-point to all
integer types.  This flag should be set for all machines, except for Cray X1 where
floating exception is generated when the floating-point value is greater than the
maximal integer value.

Platforms tested: Cray X1 and h5committest.