Cannot compile the demo to `wasm32-unknown-emscripten`

[daanboer]

I am trying to compile the demo provided in this repository to the wasm32-unknown-emscripten target. According to #1121 this is simply done by issuing

cargo build --target wasm32-unknown-emscripten

in the demo directory. However, doing so results in an error: exception handling disabled, use '-fexceptions' to enable. Fortunately, this has already been reported in a comment in #1343, and I follow the solution posted in the linked issue #1317, so I run

CXXFLAGS="-DRUST_CXX_NO_EXCEPTIONS=ON" cargo build --target wasm32-unknown-emscripten

This fixes the previous error, but instead I am now greeted with linker errors:

error: linking with `emcc` failed: exit status: 1
<omitted for brevity>
wasm-ld: warning: /home/daan/git/cxx/target/wasm32-unknown-emscripten/release/build/demo-159040b455eced30/out/libcxxbridge-demo.a: archive member '8037ba413e599e6d-main.rs.o' is neither Wasm object file nor LLVM bitcode
wasm-ld: warning: /home/daan/git/cxx/target/wasm32-unknown-emscripten/release/build/demo-159040b455eced30/out/libcxxbridge-demo.a: archive member '48d3f1b29a630f4c-blobstore.o' is neither Wasm object file nor LLVM bitcode
wasm-ld: warning: /home/daan/git/cxx/target/wasm32-unknown-emscripten/release/deps/libcxx-e355095e2e8f250f.rlib: archive member 'c16f17691ff6f04b-cxx.o' is neither Wasm object file nor LLVM bitcode
wasm-ld: warning: /home/daan/git/cxx/target/wasm32-unknown-emscripten/release/deps/liblink_cplusplus-555366c65df2217b.rlib: archive member '8d9510866275f375-dummy.o' is neither Wasm object file nor LLVM bitcode
wasm-ld: error: /home/daan/git/cxx/target/wasm32-unknown-emscripten/release/deps/demo.demo.223578a9ea247727-cgu.0.rcgu.o: undefined symbol: org$blobstore$cxxbridge1$new_blobstore_client
wasm-ld: error: /home/daan/git/cxx/target/wasm32-unknown-emscripten/release/deps/demo.demo.223578a9ea247727-cgu.0.rcgu.o: undefined symbol: cxxbridge1$unique_ptr$org$blobstore$BlobstoreClient$raw
wasm-ld: error: /home/daan/git/cxx/target/wasm32-unknown-emscripten/release/deps/demo.demo.223578a9ea247727-cgu.0.rcgu.o: undefined symbol: cxxbridge1$unique_ptr$org$blobstore$BlobstoreClient$get
wasm-ld: error: /home/daan/git/cxx/target/wasm32-unknown-emscripten/release/deps/demo.demo.223578a9ea247727-cgu.0.rcgu.o: undefined symbol: org$blobstore$cxxbridge1$BlobstoreClient$put
wasm-ld: error: /home/daan/git/cxx/target/wasm32-unknown-emscripten/release/deps/demo.demo.223578a9ea247727-cgu.0.rcgu.o: undefined symbol: cxxbridge1$unique_ptr$org$blobstore$BlobstoreClient$get
wasm-ld: error: /home/daan/git/cxx/target/wasm32-unknown-emscripten/release/deps/demo.demo.223578a9ea247727-cgu.0.rcgu.o: undefined symbol: org$blobstore$cxxbridge1$BlobstoreClient$tag
wasm-ld: error: /home/daan/git/cxx/target/wasm32-unknown-emscripten/release/deps/demo.demo.223578a9ea247727-cgu.0.rcgu.o: undefined symbol: cxxbridge1$unique_ptr$org$blobstore$BlobstoreClient$get
wasm-ld: error: /home/daan/git/cxx/target/wasm32-unknown-emscripten/release/deps/demo.demo.223578a9ea247727-cgu.0.rcgu.o: undefined symbol: org$blobstore$cxxbridge1$BlobstoreClient$metadata
wasm-ld: error: /home/daan/git/cxx/target/wasm32-unknown-emscripten/release/deps/demo.demo.223578a9ea247727-cgu.0.rcgu.o: undefined symbol: cxxbridge1$unique_ptr$org$blobstore$BlobstoreClient$drop
wasm-ld: error: /home/daan/git/cxx/target/wasm32-unknown-emscripten/release/deps/demo.demo.223578a9ea247727-cgu.0.rcgu.o: undefined symbol: cxxbridge1$unique_ptr$org$blobstore$BlobstoreClient$drop
emcc: error: '/nix/store/qz8x3jsspa8y7q9497skabscihl3d2ry-emscripten-llvm-3.1.64/bin/wasm-ld @/tmp/nix-shell.Sc6YqU/emscripten_aybnisi6.rsp.utf-8' failed (returned 1)

I am not sure why this happens, it seems that perhaps some intermediate libraries are not compiled to wasm?