Port to Qt6

[Sunderland93]

I'm still not shure how to properly do some things, e.g. check if X11 compositor is running (currently it simply checks if XComposite extension is available). Also we need to deal with scaling workarounds(Qt6 has no problem with fractional scaling)

Closes #1045

[Sunderland93]

Tested in KDE Plasma 6.2, works pretty good, so ready for review

[walmstudio]

Работает

simplescreenrecorder-2025-01-06_12.41.21.mp4

Извините, если не в том месте выложил

[4fury-c3440d8]

It works with Qt6-6.8.1. Not KDE. Thank you!

[Sunderland93]

@MaartenBaert ping

[dsheeler]

Fixed an issue of signal signature: diff.txt

diff --git a/src/GUI/PageInput.cpp b/src/GUI/PageInput.cpp
index ef5b011..2facd88 100644
--- a/src/GUI/PageInput.cpp
+++ b/src/GUI/PageInput.cpp
@@ -367,7 +367,7 @@ PageInput::PageInput(MainWindow* main_window)
 			m_checkbox_record_cursor = new QCheckBox(tr("Record cursor"), groupbox_video);
 
 			connect(m_combobox_video_backend, SIGNAL(activated(int)), this, SLOT(OnUpdateVideoAreaFields()));
-			connect(m_buttongroup_video_x11_area, SIGNAL(buttonClicked(int)), this, SLOT(OnUpdateVideoAreaFields()));
+			connect(m_buttongroup_video_x11_area, SIGNAL(buttonClicked(QAbstractButton*)), this, SLOT(OnUpdateVideoAreaFields()));
 			connect(m_combobox_x11_screens, SIGNAL(activated(int)), this, SLOT(OnUpdateVideoAreaFields()));
 			connect(m_combobox_x11_screens, SIGNAL(popupShown()), this, SLOT(OnIdentifyScreens()));
 			connect(m_combobox_x11_screens, SIGNAL(popupHidden()), this, 

SLOT(OnStopIdentifyScreens()));

[MaartenBaert]

Nice work, however you can't just remove Qt4/5 support, it's still needed for older linux distributions. I've incorporated your changes in a backward-compatible way. Let me know if you experience any issue.