Precompiled Headers and AUTORCC compilation failures

I've added a GitHub Action script to build Qt Creator with CMake 3.16.2, which has precomipled headers enabled.

The build matrix looks like this (example run)

• ✔ Windows Latest - MSVC 2019
• ❌ Windows Latest - MinGW 8.1
• ❌ Ubuntu Latest - GCC 7.2
• ✔ macOS latest - AppleClang 11

The error is:

g++.exe: error: src/libs/3rdparty/syntax-highlighting/KSyntaxHighlighting_autogen/QMMQJXFHCD/qrc_theme-data.cpp: No such file or directory
g++.exe: fatal error: no input files

The directory structure when compiled BUILD_WITH_PCH=ON (by default):

./46IEQ6DIVK
./46IEQ6DIVK/moc_definitiondownloader.cpp
./46IEQ6DIVK/moc_syntaxhighlighter.cpp
./46IEQ6DIVK/moc_theme.cpp
./include
./mocs_compilation.cpp
./moc_predefs.h
./QMMQJXFHCD
./QMMQJXFHCD/moc_definitiondownloader.cpp
./QMMQJXFHCD/moc_syntaxhighlighter.cpp
./QMMQJXFHCD/moc_theme.cpp

And the version with BUILD_WITH_PCH=OFF:

./46IEQ6DIVK
./46IEQ6DIVK/moc_definitiondownloader.cpp
./46IEQ6DIVK/moc_syntaxhighlighter.cpp
./46IEQ6DIVK/moc_theme.cpp
./include
./mocs_compilation.cpp
./moc_predefs.h
./QMMQJXFHCD
./QMMQJXFHCD/qrc_theme-data.cpp

The project should compile both with or without PCHs.