[30.x] Partial backport #34650 #34754

1. 
   hebasto commented at 12:22 pm on March 6, 2026: member

   This PR backports commits from #34650 not related to Qt update. They fix issues when building with GCC 16 and improves Qt detecting.
2. cmake: Fix `FindQt` module

   The `find_package(Qt .. MODULE REQUIRED COMPONENTS ...)` call must treat
   any missing component as a fatal error.
   
   Github-Pull: #34650
   Rebased-From: c55584575a99ff565131207916eccb3223e508a3

   916428f2c2
3. hebasto added the label Backport on Mar 6, 2026
4. 
   DrahtBot commented at 12:22 pm on March 6, 2026: contributor

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5. fanquake added this to the milestone 30.3 on Mar 6, 2026
6. 
   hebasto commented at 12:29 pm on March 6, 2026: member

   Looking into an error when cross-compiling for ARM32…
7. qt: add patch to fix build with gcc16

   Backported from:
   https://github.com/qt/qtbase/commit/7fccc79dd5744ea837ffe200bbfc9f2756870220
   
   Github-Pull: #34650
   Rebased-From: d7e972a90d59bbf705bd06f5d2606cccd1dcdcf9

   b268b4b3d4
8. qt: add patches to fix SFINAE errors/warnings with gcc16

   Meta-Issue: https://qt-project.atlassian.net/browse/QTBUG-143470
   Backports:
   
   https://github.com/qt/qtbase/commit/679e8bda1eb0cc98acb981e9a10204bed1c179f2
   https://github.com/qt/qtbase/commit/3312e89b47f8c2ea0b4263b39841c25b83a37332
   https://github.com/qt/qtbase/commit/05f201a3d559452287b20becb960de3a50249540
   
   An additional includes fix is needed after the others:
   https://github.com/qt/qtbase/commit/d68fc6ecc88a0e4532754b1a9f209881a248f4ee
   
   Github-Pull: #34650
   Rebased-From: 3cb4d6066b83348411c43587605b624f067dbbf3

   8f5c205aa9
9. qt: Add patch to fix SFINAE warnings in QAnyStringView with gcc16

   Github-Pull: #34650
   Rebased-From: 473e5f8efcdabc584b99f72c364cf15afad1ca97

   fbfc778b68
10. hebasto force-pushed on Mar 6, 2026
11. 
    hebasto commented at 8:17 pm on March 7, 2026: member

    Undrafted.
12. hebasto marked this as ready for review on Mar 7, 2026

Contributors
hebasto DrahtBot

Labels
Backport

Milestone
30.3