[suggestion] tcache double-free check

[Adhemerval Zanella]

On 23/07/2020 19:07, Eyal Itkin via Libc-alpha wrote:
> OK, in a few days I will send a patch that will use a direct call to
> getrandom so to init the key.
> As the function call may fail (maybe there won't be enough entropy),
> on failure it will default to the alternative suggestion of using
> "!tcache" instead of "tcache".

You could also get some entropy from random-bits.h, although I am not
sure if clock entropy is suffice for this specific case.