Error with Qt 6 and autotools

[Cor Blom]

Hi,

I have tried building the qt6 version using autotools in the 
buildservice of openSUSE for Tumbleweed. It fails with the following error:

[   45s] make  all-am
[   45s] make[6]: Entering directory 
'/home/abuild/rpmbuild/BUILD/lyx-qt6-2.4.1692654261.fe74c24da9/src/frontends/qt'
[   45s]   CXX      ButtonPolicy.o
[   45s]   CXX      Dialog.o
[   45s]   CXX      DialogFactory.o
[   45s]   CXX      Action.o
[   45s] In file included from Dialog.cpp:15:
[   45s] GuiView.h:22:10: fatal error: QMainWindow: No such file or 
directory
[   45s]    22 | #include <QMainWindow>
[   45s]       |          ^~~~~~~~~~~~~
[   45s] compilation terminated.
[   45s] make[6]: *** [Makefile:1015: Dialog.o] Error 1
[   45s] make[6]: *** Waiting for unfinished jobs....
[   45s] In file included from FindAndReplace.h:15,
[   45s]                  from DialogFactory.cpp:14:
[   45s] DockView.h:17:10: fatal error: QDockWidget: No such file or 
directory
[   45s]    17 | #include <QDockWidget>
[   45s]       |          ^~~~~~~~~~~~~
[   45s] compilation terminated.
[   45s] make[6]: *** [Makefile:1015: DialogFactory.o] Error 1
[   45s] In file included from Action.cpp:14:
[   45s] GuiApplication.h:21:10: fatal error: QApplication: No such file 
or directory
[   45s]    21 | #include <QApplication>
[   45s]       |          ^~~~~~~~~~~~~~
[   45s] compilation terminated.

Those files that can't be found are present. I have also tried cmake and 
there the compilation succeeds. Exactly the same environment. It seems 
that in autoconf something is missing?

Everything is fine with Qt 5, BTW.

Regards,

Cor