wasmtime-py 0.16.1 regression

Unfortunately since 0.16.1 it looks like every binary crashes on exit:

Traceback (most recent call last):
  File "/home/whitequark/.local/bin/yosys", line 11, in <module>
    load_entry_point('yosys', 'console_scripts', 'yosys')()
  File "/home/whitequark/Projects/yosys-pypi/yosys/__init__.py", line 57, in _run_yosys_argv
    run_yosys(sys.argv)
  File "/home/whitequark/Projects/yosys-pypi/yosys/__init__.py", line 55, in run_yosys
    _run_wasm_app("yosys.wasm", argv)
  File "/home/whitequark/Projects/yosys-pypi/yosys/__init__.py", line 51, in _run_wasm_app
    app.exports["_start"]()
  File "/home/whitequark/.local/lib/python3.7/site-packages/wasmtime/_func.py", line 120, in __call__
    raise Trap.__from_ptr__(trap)
wasmtime._trap.Trap: explicitly exited

[alexcrichton]

This is due to https://github.com/bytecodealliance/wasmtime/pull/1646, and I think we need to enhance the C API with accessors to see if something exited, so bindings can be added for “was this an exit trap” and the trap can be raised with a different error perhaps.

[whitequark]

Yeah, the only issue is the tag itself.