[LyX/master] By report autoconf 2.71 works, 2.70 is known to have compatibility issues.

[Pavel Sanda]

On Mon, Feb 22, 2021 at 11:07:04AM +0100, Pavel Sanda wrote:
> commit ddb8bd624af1493adea05e2e0a74d2a27f934e01
> Author: Pavel Sanda <sanda at lyx.org>
> Date:   Mon Feb 22 11:09:22 2021 +0100
> 
>     By report autoconf 2.71 works, 2.70 is known to have compatibility issues.

Anyone around with 2.70 installed to check whether the reported issues
affect us? (Not a big deal, no sane distribution will deliver 2.70 with
those issues as a default).

Pavel