[REG] QDoc: Could not find the module header, even with `moduleheader =`

qt.qdoc: Start qdoc for Platform Integration in dual process mode: prepare phase.
(qdoc) Could not find the module header in include paths for module "Platform Integration" (include paths: QList("-I/Users/torarne/dev/qt/6.0/qtdoc/doc/src/platformintegration", "-I/Users/torarne/build/qt/6.0-qmake/qtdoc/doc/src/platformintegration", "-I/Users/torarne/dev/qt/6.0/qtbase/mkspecs/macx-clang", "-I/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1", "-I/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/12.0.0/include", "-I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include", "-I/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include") )
Artificial module header built from header dirs in qdocconf file

but qdocconf has:

1. Instruct Clang not to look for a module header
   moduleheader =