[PATCHv2] malloc: Make sure tcache_key is odd enough

[Wilco Dijkstra]

Hi,

> I thought that exactly 80 columns was acceptable, but the GNU
> standards disagree:
>
> | Please keep the length of source lines to 79 characters or less, for
> | maximum readability in the widest range of environments.
> 
> <https://www.gnu.org/prep/standards/html_node/Formatting.html>

We should really increase that limit a little. It's 2025 after all, not 1980 -
everyone has huge screens...

Cheers,
Wilco