od: don’t assume no holes in wide unsigned

od: don’t assume no holes in wide unsigned

Also, fix minor related typos.
* src/od.c (MAX_INTEGRAL_TYPE_SIZE, MAX_ADDRESS_LENGTH):
Now a constant, not a macro.
(MAX_INTEGRAL_TYPE_WIDTH): New constant.  Use it instead of
CHAR_BIT, so as not to assume that uintmax_t and unsigned long
long int are hole-free.  This doesn’t matter on practical porting
targets, though there is still a mainframe or two that have holes.
(FMT_BYTES_ALLOCATED): Fix typo by changing "jd" to "jo".
Fix off-by-one typo in static assertion.