PATCH: restore global.c to compilability

[Joern Rennecke]

> A macro that just expanded to `conflicts + allocno * allocno_row_words'
> would be effective.

I thought about that, and it could be used in four other places
(SET_CONFLICT, CONFLICTP, and the two places that currently use
 ialloc_prod), but the name of that macro would have to be pretty
long to be meaningful, and then we'd get visual uglyness.

> Ok.

Checked in.