[Bug bootstrap/68540] 6.0 build process broken on Linux Mint, potential include ordering problem

[tschwinge at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68540

--- Comment #9 from Thomas Schwinge <tschwinge at gcc dot gnu.org> ---
(In reply to Martin Reinecke from comment #8)
> In order to save others some head-scratching, would it be possible to update
> the ISL version check in the configuration machinery so that it gives a
> clear error when encountering an ISL version that is too old?

Done in r231706.