Qt & gcc requirements for 2.4

[Jean-Marc Lasgouttes]

Le 14/11/2022 à 11:25, Pavel Sanda a écrit :
> Hi,
> 
> since (at least) fff28c57561a our master does not compile with gcc 4.9 anymore.
> Also it seems that there is agreement that Qt4 won't be supported for 2.4 either.
> What should we state in the INSTALL now?
> 
> I guess that boils down to two separate questions:
> 
> - minimal (theoretical) requirements:
>    I see JMarc dropped  __cplusplus >= 201402L, what it means in term of gcc(clang)?
>    Is there someone running Qt < 5.15?

Des dropping this cause a break in gc 4.9? If so I can revert that.

I compile LyX with gcc 7.5.0 and Qt 4.8.7  on a ubuntu 18.04 VM. This is 
the oldest reasonable distrib I could find.

> - real tested combinations:
>    What are the real Qt numbers/gcc(/..) numbers we use?

gcc 9.4.0 and Qt 5.12.8 on ubuntu 20.04.

JMarc