install fails under PyPy

~I believe the wsaccel dependency pulls in autobahn, which in turn fails under PyPy due to https://github.com/crossbario/autobahn-python/issues/968.~



The wsaccel dependency fails under PyPy:



```

$ pip_pypy3 install trio_websocket

Collecting trio_websocket

  Downloading https://files.pythonhosted.org/packages/1d/5b/40c701f1ddadf1b8e055b2378fe992acd43de1c3e72a07807f327fe5f390/trio-websocket-0.7.0.tar.gz

Requirement already satisfied: async_generator<2,>=1.10 in /usr/local/Cellar/pypy3/7.0.0/libexec/site-packages (from trio_websocket) (1.10)

Collecting ipaddress<2,>=1.0.22 (from trio_websocket)

  Using cached https://files.pythonhosted.org/packages/fc/d0/7fc3a811e011d4b388be48a0e381db8d990042df54aa4ef4599a31d39853/ipaddress-1.0.22-py2.py3-none-any.whl

Requirement already satisfied: trio>=0.11 in /usr/local/Cellar/pypy3/7.0.0/libexec/site-packages (from trio_websocket) (0.11.0)

Collecting wsaccel<0.7,>=0.6.2 (from trio_websocket)

  Using cached https://files.pythonhosted.org/packages/52/46/9ef0744b434ac723ae3aeddcb92ab29af14f8912f53f47590b5a0db0b9d6/wsaccel-0.6.2.tar.gz

Collecting wsproto<0.15,>=0.14 (from trio_websocket)

  Downloading https://files.pythonhosted.org/packages/6a/e2/d69646c06cc970393e23e7506cb7ec3cec98e1f54ca5c5fac6efc15f67de/wsproto-0.14.1-py2.py3-none-any.whl

Collecting yarl<2,>=1.2.6 (from trio_websocket)

  Using cached https://files.pythonhosted.org/packages/fb/84/6d82f6be218c50b547aa29d0315e430cf8a23c52064c92d0a8377d7b7357/yarl-1.3.0.tar.gz

Requirement already satisfied: attrs>=18.2.0 in /usr/local/Cellar/pypy3/7.0.0/libexec/site-packages (from trio>=0.11->trio_websocket) (19.1.0)

Requirement already satisfied: sortedcontainers in /usr/local/Cellar/pypy3/7.0.0/libexec/site-packages (from trio>=0.11->trio_websocket) (2.1.0)

Requirement already satisfied: idna in /usr/local/Cellar/pypy3/7.0.0/libexec/site-packages (from trio>=0.11->trio_websocket) (2.8)

Requirement already satisfied: outcome in /usr/local/Cellar/pypy3/7.0.0/libexec/site-packages (from trio>=0.11->trio_websocket) (1.0.0)

Requirement already satisfied: sniffio in /usr/local/Cellar/pypy3/7.0.0/libexec/site-packages (from trio>=0.11->trio_websocket) (1.1.0)

Requirement already satisfied: contextvars>=2.1; python_version < "3.7" in /usr/local/Cellar/pypy3/7.0.0/libexec/site-packages (from trio>=0.11->trio_websocket) (2.4)

Collecting h11>=0.8.1 (from wsproto<0.15,>=0.14->trio_websocket)

  Downloading https://files.pythonhosted.org/packages/5a/fd/3dad730b0f95e78aeeb742f96fa7bbecbdd56a58e405d3da440d5bfb90c6/h11-0.9.0-py2.py3-none-any.whl (53kB)

    100% |████████████████████████████████| 61kB 1.4MB/s

Collecting multidict>=4.0 (from yarl<2,>=1.2.6->trio_websocket)

  Downloading https://files.pythonhosted.org/packages/7f/8f/b3c8c5b062309e854ce5b726fc101195fbaa881d306ffa5c2ba19efa3af2/multidict-4.5.2.tar.gz (105kB)

    100% |████████████████████████████████| 112kB 4.1MB/s

Requirement already satisfied: immutables>=0.9 in /usr/local/Cellar/pypy3/7.0.0/libexec/site-packages (from contextvars>=2.1; python_version < "3.7"->trio>=0.11->trio_websocket) (0.9)

Installing collected packages: ipaddress, wsaccel, h11, wsproto, multidict, yarl, trio-websocket

  Running setup.py install for wsaccel ... error

    Complete output from command /usr/local/Cellar/pypy3/7.0.0/bin/pypy3 -u -c "import setuptools, tokenize;__file__='/private/var/folders/ww/51xbs7nx6t16x7mh225q9x1h0000gn/T/pip-install-dc6tdoqk/wsaccel/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" install --record /private/var/folders/ww/51xbs7nx6t16x7mh225q9x1h0000gn/T/pip-record-8umwani7/install-record.txt --single-version-externally-managed --compile:

    running install

    running build

    running build_py

    creating build

    creating build/lib.macosx-10.13-x86_64-3.6

    creating build/lib.macosx-10.13-x86_64-3.6/wsaccel

    copying wsaccel/__init__.py -> build/lib.macosx-10.13-x86_64-3.6/wsaccel

    running build_ext

    building 'wsaccel.utf8validator' extension

    creating build/temp.macosx-10.13-x86_64-3.6

    creating build/temp.macosx-10.13-x86_64-3.6/wsaccel

    gcc -pthread -arch x86_64 -DNDEBUG -O2 -fPIC -I/usr/local/Cellar/pypy3/7.0.0/libexec/include -c wsaccel/utf8validator.c -o build/temp.macosx-10.13-x86_64-3.6/wsaccel/utf8validator.o

    wsaccel/utf8validator.c:235:11: warning: 'PyMethod_New' macro redefined [-Wmacro-redefined]

      #define PyMethod_New(func, self, klass) ((self) ? PyMethod_New(func, self) : PyInstanceMethod_New(func))

              ^

    /usr/local/Cellar/pypy3/7.0.0/libexec/include/pypy_decl.h:487:9: note: previous definition is here

    #define PyMethod_New PyPyMethod_New

            ^

    wsaccel/utf8validator.c:983:49: warning: passing 'void **' to parameter of type 'const void **' discards qualifiers in nested pointer types [-Wincompatible-pointer-types-discards-qualifiers]

      __pyx_t_1 = PyObject_AsReadBuffer(__pyx_v_ba, ((void **)(&__pyx_v_buf)), (&__pyx_v_buf_len)); if (unlikely(__pyx_t_1 == -1)) {__pyx_filename = __pyx_f[0]; __pyx_lineno = 104; __pyx_clineno = __LINE__; goto __pyx_L1_error;}

                                                    ^~~~~~~~~~~~~~~~~~~~~~~~~

    /usr/local/Cellar/pypy3/7.0.0/libexec/include/object.h:333:64: note: passing argument to parameter here

    PyAPI_FUNC(int) PyObject_AsReadBuffer(PyObject *, const void **, Py_ssize_t *);

                                                                   ^

    2 warnings generated.

    gcc -pthread -shared -undefined dynamic_lookup build/temp.macosx-10.13-x86_64-3.6/wsaccel/utf8validator.o -o build/lib.macosx-10.13-x86_64-3.6/wsaccel/utf8validator.pypy3-70-darwin.so

    clang: warning: argument unused during compilation: '-pthread' [-Wunused-command-line-argument]

    building 'wsaccel.xormask' extension

    gcc -pthread -arch x86_64 -DNDEBUG -O2 -fPIC -I/usr/local/Cellar/pypy3/7.0.0/libexec/include -c wsaccel/xormask.c -o build/temp.macosx-10.13-x86_64-3.6/wsaccel/xormask.o

    wsaccel/xormask.c:235:11: warning: 'PyMethod_New' macro redefined [-Wmacro-redefined]

      #define PyMethod_New(func, self, klass) ((self) ? PyMethod_New(func, self) : PyInstanceMethod_New(func))

              ^

    /usr/local/Cellar/pypy3/7.0.0/libexec/include/pypy_decl.h:487:9: note: previous definition is here

    #define PyMethod_New PyPyMethod_New

            ^

    wsaccel/xormask.c:2165:36: error: no member named 'curexc_traceback' in 'struct _ts'

            PyObject* tmp_tb = tstate->curexc_traceback;

                               ~~~~~~  ^

    wsaccel/xormask.c:2168:21: error: no member named 'curexc_traceback' in 'struct _ts'

                tstate->curexc_traceback = tb;

                ~~~~~~  ^

    1 warning and 2 errors generated.

    error: command 'gcc' failed with exit status 1



    ----------------------------------------

Command "/usr/local/Cellar/pypy3/7.0.0/bin/pypy3 -u -c "import setuptools, tokenize;__file__='/private/var/folders/ww/51xbs7nx6t16x7mh225q9x1h0000gn/T/pip-install-dc6tdoqk/wsaccel/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" install --record /private/var/folders/ww/51xbs7nx6t16x7mh225q9x1h0000gn/T/pip-record-8umwani7/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /private/var/folders/ww/51xbs7nx6t16x7mh225q9x1h0000gn/T/pip-install-dc6tdoqk/wsaccel/

```

[]