wasm: creator cannot build webassembly app

Creator detected Emscripten 1.39.8 fine, but when I try building a webassembly example (textedit), QtCreator build fails with this error:

emscripten:INFO: generating system asset: is_vanilla.txt... (this will be cached in "/Users/lpotter/.emscripten_cache/is_vanilla.txt" for subsequent builds)
emscripten:INFO: - ok
shared:WARNING: LLVM version appears incorrect (seeing "11.0", expected "9.0")
shared:WARNING: (Emscripten: settings file has changed, clearing cache)
shared:INFO: (Emscripten: Running sanity checks)
shared:ERROR: Cannot find /Users/lpotter/emsdk/upstream/bin/lli, check the paths in ~/.emscripten
make: *** [textedit.o] Error 1
04:04:37: The process "/usr/bin/make" exited with code 2.
Error while building/deploying project textedit (kit: Qt 5.15.0 WebAssembly)
The kit Qt 5.15.0 WebAssembly has configuration issues which might be the root cause for this problem.
When executing step "Make"

There is no file /Users/lpotter/emsdk/upstream/bin/lli

lli only seems to be present in the older 1.38.x series of emscripten.