qt6.qtbase: add patch to fix handling of variable fonts

[NickCao]

Description of changes

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 23.05 Release Notes (or backporting 22.11 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

[oxalica]

Works for me. Tested with tdesktop.

[Mathnerd314]

For reference, the patch was submitted to the Qt project 5 days ago at https://bugreports.qt.io/browse/QTBUG-111994 by a Fedora contributor. There seems to also be a issue with bold and other non-regular styles, https://bugreports.qt.io/browse/QTBUG-112136, which doesn't yet have a correct patch.

[Mathnerd314]

And this issue only applies the patch to Qt6. Looking at Fedora they are applying this fix to Qt5: https://bugzilla.redhat.com/show_bug.cgi?id=2178389. I guess Qt5 will cause a massive rebuild though so should be a separate PR on staging.

[Mathnerd314]

Qt isn't really my area of expertise but I don't see anything wrong with including a patch from Fedora.