Include directories wrong for Qt framework built with -libinfix

When building Qt on mac with a custom libinfix, and then setting it up in Qt Creator, Qt Creator can't find any Qt includes.

Repro steps:

First build Qt with a custom libinfix:

./configure -qtnamespace TestNameSpace -qtlibinfix TestSuffix -opensource -confirm-license -nomake examples -nomake tests
make module-qtbase module-qttools
sudo make module-qtbase-install_subtargets module-qttools-install_subtargets

Then in Qt Creator (4.12.0) create a new Qt Version pointing to the newly built Qt framework (/usr/local/Qt-5.14.2/bin/) and a Kit using that Qt Version.

Then create a new "Qt Widgets Application". You'll see the following issue: https://i.imgur.com/8JiQZVy.png

If I don't use the libinfix option, the test app has no problem finding the includes: https://i.imgur.com/RR7MYsR.png

This is related to https://bugreports.qt.io/browse/QTBUG-83912