finally, a version that generalizes well

finally, a version that generalizes well

While it's not always strictly a win,
it's a win for files that see a noticeably compression ratio increase,
while it's a very small noise for other files.

Downside is, this patch is less efficient for 32-bit arrays of integer
than the previous patch which was introducing losses for other files,
but it's still a net improvement on this scenario.