vchoi_fork

[svn-r11395] Purpose: Bug fix

Description: Quincey added the condition branch (else if (*((ST*)S) != (ST)((DT)(*((ST*)S)))))
in the definition of the macro H5T_CONV_Fx_CORE.  It handles a special situation
when the source is "float" and assigned the value of "INT_MAX".  Compilers do roundup
making this value "INT_MAX+1".  This branch is to check that situation and return
exception for some compilers, mainly GCC.

The branch if (*((ST*)S) > (DT)(D_MAX) || (S_PREC < D_PREC && *((ST*)S) ==
(DT)(D_MAX))) is for some compilers like Sun, HP, IBM, and SGI where under
the same situation the "int" doesn't overflow.

A test was added to dt_arith.c to check 2 conversions, from float to int where the
float is INT_MAX, and from double to signed char where the double is SCHAR_MAX.


Platforms tested: h5committest and fuss.