[LyX/2.3.x] Qt4 compilable again

[Jean-Marc Lasgouttes]

Le 24/11/2022 à 17:21, José Matos a écrit :
> Probably here it does not mater but in general the safer version would
> be to move the parenthesis from right to let, i.e.
> 
>   (degree) * M_PI/180
> 
> I am thinking about examples like qDegreesToRadians(a+b)

I did that on master. Note that I have doubts that we want to support Qt 
5.0.x. What would be a good first usable version ? Versions history 
suggest that Qt5.3 or 5.4 would be contemporary with gcc 4.9, our oldest 
supported compiler.

I read at some time that Qt 5.6 is the first really good version (and 
LTS), but this is 2016-era.

Shall we do something, or just accept all Qt5 versions?

JMarc