qmltc and relocatable qt builds

i'm trying to use the qml type compiler with statically linked qt. my typical workflow is to:

build qt:

• build qt on the build server
• create a tarball of the folder (after ninja install)
• deploy qt to an artifact storage

use qt:

• download qt from the artifact storage and extract
• use set the cmake prefix path to the location where qt is extracted to

when using qmltc, i'm now getting the following error:
```
Warning: Failed to find the following builtins: builtins.qmltypes, jsroot.qmltypes (so will use qrc). Import paths used:
/Volumes/build/bamboo-build/THIRDP-QT98-BAMN/sources/Qt-6.3.0-R1-macx-clang-static/qml
```

this import path is pointing to the folder which is used when compiling qt (it seems to be compiled into the binary?), but it is invalid when using qt.

makes me wonder if the qml import path could be inferred from the location of the qmltc binary, as it's located int `/path/to/qt/bin/qmltc`, while the qml import folder is in `/path/to/qt/qml`.