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

[Jean-Marc Lasgouttes]

Le 05/11/2024 à 09:50, Pavel Sanda a écrit :
>> Everything compiles fine with gcc 7 and Qt 5.9.5.
>>
>> Are we happy now?
> 
> I think this was good move. Pavel

And we have the possibility to switch to gcc 8 on this platform if the 
C++17 support is not sufficient.

JMarc