Rename GCC_DIAG_OFF/ON macros to H5_GCC_DIAG_OFF/ON and move from
src/H5private.h to src/H5public.h. Wrap typedef of hsize_t and hssize_t
in DIAG_OFF(long-long) macros.
Clean up a bunch of "macro '-' is unused" warnings.
Tested on:
Mac OSX/64 10.9.2 (amazon) w/gcc 4.8.2, C++, FORTRAN, parallel
(too minor to require h5committest)