trouble configuring QtPDF for iOS

$ ../qt6/configure -developer-build -xplatform macx-ios-clang -qt-host-path ~/dev/qt6-dbg/qtbase -submodules qtbase,qtdeclarative,qttools,qtshadertools,qtwebengine -no-feature-qtwebengine-build
...
  Qt PDF:
    Support V8 ........................... no
    Support XFA .......................... no
    Support XFA-BMP ...................... no
    Support XFA-GIF ...................... no
    Support XFA-PNG ...................... no
    Support XFA-TIFF ..................... no
    Bitcode support ...................... yes
    Use static runtime ................... no


Note: Using static linking will disable the use of dynamically loaded plugins. Make sure to import all needed static plugins, or compile needed modules into the library.

WARNING: QDoc will not be compiled, probably because clang's C and C++ libraries could not be located. This means that you cannot build the Qt documentation.
You may need to set CMAKE_PREFIX_PATH or LLVM_INSTALL_DIR to the location of your llvm installation.
Other than clang's libraries, you may need to install another package, such as clang itself, to provide the ClangConfig.cmake file needed to detect your libraries. Once this
file is in place, the configure script may be able to detect your system-installed libraries without further environment variables.
On macOS, you can use Homebrew's llvm package.
You will also need to set the FEATURE_clang CMake variable to ON to re-evaluate this check.
WARNING: The Clang-based lupdate parser will not be available. Suitable LLVM and Clang C++ libraries have not been found. You will need to set the FEATURE_clangcpp CMake variable to ON to re-evaluate this check.
WARNING: QtPdf has warnings.
 -- The following configure warnings were found:
 * No harfbuzz library at least 4.3.0 version or later. Using build-in one
 * No glib library at least 2.32.0 version or later. Using build-in one
WARNING: QtWebEngine has warnings.
 -- The following configure warnings were found:
 * No harfbuzz library at least 4.3.0 version or later. Using build-in one
 * No glib library at least 2.32.0 version or later. Using build-in one
WARNING: QtWebEngine won't be built.
 -- The following configure errors were found:
 * AppleClang compiler is not supported.
 * Static build is not supported.
 * Build can be done only on Linux, Windows or macOS.

--

Qt is now configured for building. Just run 'cmake --build . --parallel'

Once everything is built, Qt is installed. You should NOT run 'cmake --install .'
Note that this build cannot be deployed to other machines or devices.

To configure and build other Qt modules, you can use the following convenience script:
        /Users/rutledge/dev/qt6-ios/qtbase/bin/qt-configure-module

If reconfiguration fails for some reason, try removing 'CMakeCache.txt' from the build directory
Alternatively, you can add the --fresh flag to your CMake flags.

-- Configuring done (50.5s)
-- Generating done (2.0s)
-- Build files have been written to: /Users/rutledge/dev/qt6-ios