[LyX/master] Cmake build: Start demanding at least version 5.1 if compiling with gcc

[Pavel Sanda]

On Thu, Oct 24, 2024 at 12:43:49PM +0000, Kornel Benko wrote:
> commit d6fba3b94e54ac58806d7cb65584edfdbe6d515e
> Author: Kornel Benko <kornel at lyx.org>
> Date:   Thu Oct 24 14:52:22 2024 +0200
> 
>     Cmake build: Start demanding at least version 5.1 if compiling with gcc

We just agreed on GCC >= 8.
Pavel