Looks okay in a quick glance, except error message spelling is poor:

! #define ARRISNULL(x) ( (x) ? ( ( ARR_NDIM(x) == NDIM ) ? ( ( ARRNELEMS( x ) )
? 0 : 1 ) : ( ( ARR_NDIM(x) ) ? (elog(ERROR,"Array is not one-dimentional: %d di
mentions", ARR_NDIM(x)),1) : 1 ) ) : 1 )

Should be "one-dimensional" and "dimensions".  Bruce, would you fix that
when you apply it?

Tom