- introduce a hypothetical new audio api 'openal'
- some EMSCRIPTEN conditionals
- ignore missing boost pthreads for now

The cmake command for now is:

    $ emcmake cmake -DSC_WII=no -DSC_EL=no -DSUPERNOVA=no -DSC_HIDAPI=no -DNO_LIBSNDFILE=yes -DSC_QT=no -DNO_AVAHI=yes -DSC_ABLETON_LINK=no -DCMAKE_BUILD_TYPE="Release" -Wno-dev -s USE_PTHREADS=1 -DPTHREADS_LIBRARY=ignore --target scsynth ..

- until the missing audio API is detected

- add some more preprocessor conditionals
- now we get an initial list of undefined symbols
  (mostly: initialization of audio API, some pthread, some file system)

- we have unstaged commits in `external_libraries/nova-tt`; thus
  next step will be to commit them in a fork of nova-tt

- use nova-tt fork (branch wasm)
- I ran `update --remote`; was this a good idea?

- make succeeds now

- seems we had flags on emcmake that were never passed to emcc
- we have a strange linker error regarding shared memory
- now with shared memory actually enabled, we cannot run in Firefox
  without user adjustments
- in Chromium, there is an error enumerating audio/video devices
- some problem now in boost

    at boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>::priv_add_segment(void*, unsigned long) (http://0.0.0.0:8000/scsynth.wasm:wasm-function[4452]:0xceebe)

This may be a problem due to assuming _no_ shared memory in previous
preprocessor tuning; perhaps we need to remove those diversions again

```
abort @ scsynth.js:1475
___assert_fail @ scsynth.js:2082
boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>::priv_add_segment(void*, unsigned long) @ scsynth.wasm:1
boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>::rbtree_best_fit(unsigned long, unsigned long) @ scsynth.wasm:1
boost::interprocess::segment_manager_base<boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul> >::segment_manager_base(unsigned long, unsigned long) @ scsynth.wasm:1
boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>, boost::interprocess::iset_index>::segment_manager(unsigned long) @ scsynth.wasm:1
boost::interprocess::ipcdetail::basic_managed_memory_impl<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>, boost::interprocess::iset_index, 16ul>::create_impl(void*, unsigned long) @ scsynth.wasm:1
boost::interprocess::ipcdetail::create_open_func<boost::interprocess::ipcdetail::basic_managed_memory_impl<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>, boost::interprocess::iset_index, 16ul> >::operator()(void*, unsigned long, bool) const @ scsynth.wasm:1
void boost::interprocess::ipcdetail::managed_open_or_create_impl<boost::interprocess::shared_memory_object, 16ul, true, false>::priv_open_or_create<boost::interprocess::ipcdetail::create_open_func<boost::interprocess::ipcdetail::basic_managed_memory_impl<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>, boost::interprocess::iset_index, 16ul> > >(boost::interprocess::ipcdetail::create_enum_t, char const* const&, unsigned long, boost::interprocess::mode_t, void const*, boost::interprocess::permissions const&, boost::interprocess::ipcdetail::create_open_func<boost::interprocess::ipcdetail::basic_managed_memory_impl<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>, boost::interprocess::iset_index, 16ul> >) @ scsynth.wasm:1
boost::interprocess::ipcdetail::managed_open_or_create_impl<boost::interprocess::shared_memory_object, 16ul, true, false>::managed_open_or_create_impl<boost::interprocess::ipcdetail::create_open_func<boost::interprocess::ipcdetail::basic_managed_memory_impl<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>, boost::interprocess::iset_index, 16ul> > >(boost::interprocess::open_or_create_t, char const* const&, unsigned long, boost::interprocess::mode_t, void const*, boost::interprocess::ipcdetail::create_open_func<boost::interprocess::ipcdetail::basic_managed_memory_impl<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>, boost::interprocess::iset_index, 16ul> > const&, boost::interprocess::permissions const&) @ scsynth.wasm:1
boost::interprocess::basic_managed_shared_memory<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>, boost::interprocess::iset_index>::basic_managed_shared_memory(boost::interprocess::open_or_create_t, char const*, unsigned long, void const*, boost::interprocess::permissions const&) @ scsynth.wasm:1
detail_server_shm::server_shared_memory_creator::server_shared_memory_creator(unsigned int, unsigned int) @ scsynth.wasm:1
World_New @ scsynth.wasm:1
```

- somehow it hangs if we call `EventLoop::run([world]() { World_WaitForQuit(world, true); });`
  so skip that for now

- add a 'boot' button so we don't run into the problem of
  having an AudioContext that doesn't start

- so all pieces are in place, OSC messages seem to be correctly encoded
- audio driver start/stop now in place
- but we get these errors:

Uncaught TypeError: Failed to execute 'copyToChannel' on 'AudioBuffer': The provided ArrayBufferView value must not be shared.
    at ScriptProcessorNode.ad.proc.onaudioprocess (scsynth.js:1688)
ad.proc.onaudioprocess @ scsynth.js:1688

It seems that because of `-pthread`, the HEAP is now backed by
`SharedArrayBuffer`, and that in turn cannot be used in `copyToChannel`.

Hopefully, we can just make one additional copy. If not, we're f*cked
:-O

- for example, trying to d_recv analog-bubbles,
  the first UGen encountered, 'Control' is apparently not
  installed
- probably we need to include some binary file for the
  emscripten virtual file system

- DiskIO is disabled because we currently don't build with libsndfile
  (perhaps it's possible -- I don't remember why I had to disable it)

- we need to understand how to allocate (and free) the
  memory for OSC replies. is web_reply_func called from
  different threads? Can we just use malloc, or should we
  use rt memory?

- noticed a bug in `NumOutputBuses`

- extraneous constructor argument `int inNumSamples` was causing crashes

- wasm/configure.sh : use release build type
  (we're still catching exceptions, though)

- probably the originally missing symbols were due to
  wrong pthread linker settings
- go back to timblechmann's repo

- seems the assertion in rbtree_best_fit.hpp
  does hold now

- build file seems ok for now

- Module.oscDriver is now a dictionary from
  virtual port number to an object that at least
  defines the property `receive`, a function taking
  two arguments: sender's port, and Uint8Array raw OSC packet.

- needed to do anything more involving like allocating larger buffers