Yes, I've updated the patch [1], but I still have a problem loading dynlibs for TH in some cases. I don't think it's related to Cabal (which appears to be running all the right commands), but I can't completely rule it out either.
The Cabal patch was fine indeed. It was a problem with the internal names of some GHCJS dynlibs, so the system linker did not always pick up dependencies correctly.