* gencode.c, interp.c: Replaced explicit long long references with
WORD64HI, WORD64LO, SET64HI and SET64LO macro calls.
* support.h (SET64LO, SET64HI): Macros added.
This is an intermediate checkin. The work of removing "long long"
usage is not yet finished. These changes are clean, and have been
sitting on my machine for a while (whilst doing other work), and it is
safer for them to be checked in.
a647a859cb