-Replace codes.h with iberror.h (or remove)
-Move gds__vax_integer and gds__event_block* to alt.cpp and isc_ to gds.cpp
-Use ISC_QUAD internally
-Use isc_vax_integer internally
o since the define 'VAX' was only used to tell that the byte order is
LITTLE_ENDIAN (it have nothing else to do with the VAX computer family)
it can safely replaced with '!WORDS_BIGENDIAN'.
o check if pointers are 64 bit
o replaced HAS_64BIT_POINTERS with 'SIZEOF_VOID_P == 8'
