Fix build with Qt6.10

[DarthGandalf]

https://bugs.gentoo.org/966288

Description

Fixes # (issue)

Screenshots (if appropriate):

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• This change requires a documentation update
• Housekeeping

How Has This Been Tested?

Test Configuration:

• Operating system: <Name, version number>
• Graphics Card: <Manufacturer (likely Intel, NVidia, AMD?), Model (HD, Geforce, Radeon..., with model number), driver version?>

Checklist:

• My code follows the code style of this project.
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (header file)
• I have updated the respective chapter in the Stellarium User Guide
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[alex-w]

The second patch is better, but not very accurate still…

[DarthGandalf]

What else is missing?

I thought about comparing Qt${QT_VERSION_MAJOR}_VERSION instead of Qt6_VERSION, but this seems clearer to me, and in the case of Qt5 it's also false as expected

[alex-w]

What else is missing?

Not missing, but splitting option onto parts may be painful in future…

I thought about comparing Qt${QT_VERSION_MAJOR}_VERSION instead of Qt6_VERSION, but this seems clearer to me, and in the case of Qt5 it's also false as expected

Comparing Qt${QT_VERSION_MAJOR}_VERSION is better, but you are right - Qt6_VERSION seems clearer here. In any way comments is needed here.

[DarthGandalf]

Added comment