reproduce bug qt6...metatypes.json: illegal value (windows nmake)

[pestophagous]

Adding a very simple CMakeLists.txt, main.cpp, and Main.qml, along with some scripts so that this is compiled in a GitHub CI runner for win64_msvc2019_64 using Qt 6.5.3.

This reproduces the issue described at https://forum.qt.io/topic/146961/building-qt6-5-with-nmake-error

However, skip ahead to the very next PR in this repo (a PR that will also be marked as draft and then closed without merging it), and in the next PR (PR #121) you can see that updating from Qt 6.5.3 to Qt 6.7.3 eliminates the problem. 🎉

with nmake on win64_msvc2019_64 using Qt 6.5.3 (as in this PR), the error looks like:

[ 25%] Built target appReproducejsonbug_automoc_json_extraction
	"C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Tools\MSVC\14.29.30133\bin\HOSTx64\x64\nmake.exe"  -f CMakeFiles\appReproducejsonbug.dir\build.make /nologo -L                  CMakeFiles\appReproducejsonbug.dir\depend
[ 30%] Automatic QML type registration for target appReproducejsonbug
	call .qt\bin\qt_setup_tool_path.bat D:/a/qt-qml-project-template-with-ci/qt-qml-project-template-with-ci/dl_third_party/Qt_desktop/6.5.3/msvc2019_64/./bin/qmltyperegistrar.exe --generate-qmltypes=D:/a/qt-qml-project-template-with-ci/qt-qml-project-template-with-ci/cbuild/Reproducejsonbug/appReproducejsonbug.qmltypes --import-name=Reproducejsonbug --major-version=1 --minor-version=0 @D:/a/qt-qml-project-template-with-ci/qt-qml-project-template-with-ci/cbuild/qmltypes/appReproducejsonbug_foreign_types.txt -o D:/a/qt-qml-project-template-with-ci/qt-qml-project-template-with-ci/cbuild/appreproducejsonbug_qmltyperegistrations.cpp D:/a/qt-qml-project-template-with-ci/qt-qml-project-template-with-ci/cbuild/meta_types/qt6appreproducejsonbug_debug_metatypes.json
Error 5 while parsing D:/a/qt-qml-project-template-with-ci/qt-qml-project-template-with-ci/cbuild/meta_types/qt6appreproducejsonbug_debug_metatypes.json: illegal value
NMAKE : fatal error U1077: 'call' : return code '0x1'
Stop.

As shown in the log: https://github.com/219-design/qt-qml-project-template-with-ci/actions/runs/14743379442

(However, the log will expire after a few days. You'd want to clone or fork this repro if you have any desire to reproduce this again.)

[pestophagous]

if for any reason you have to use 6.5.3 and work around this bug, then uncomment the workaround shown here on lines 46,47,48,49

[pestophagous]

Closing. This was always simply for testing and never intended to merge.