Building for Python 3.x in MacOS fails

[jj-globant]

Using Conda for the environment, Xcode is installed and everything is updated, but i get this errors when executing the 'pip install'

Collecting python-cjson
  Using cached python-cjson-1.2.1.tar.gz
Building wheels for collected packages: python-cjson
  Running setup.py bdist_wheel for python-cjson ... error
  Complete output from command /Users/juanjose.lopez/anaconda/envs/ChevereBot/bin/python -u -c "import setuptools, tokenize;__file__='/private/var/folders/kn/6ynmt1p91jvdkbv869lkz6vm4c1z19/T/pip-build-guitqjom/python-cjson/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" bdist_wheel -d /var/folders/kn/6ynmt1p91jvdkbv869lkz6vm4c1z19/T/tmpn3y8rvi_pip-wheel- --python-tag cp36:
  running bdist_wheel
  running build
  running build_ext
  building 'cjson' extension
  creating build
  creating build/temp.macosx-10.7-x86_64-3.6
  gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -I/Users/juanjose.lopez/anaconda/envs/ChevereBot/include -arch x86_64 -I/Users/juanjose.lopez/anaconda/envs/ChevereBot/include -arch x86_64 -DMODULE_VERSION=1.2.1 -I/Users/juanjose.lopez/anaconda/envs/ChevereBot/include/python3.6m -c cjson.c -o build/temp.macosx-10.7-x86_64-3.6/cjson.o
  cjson.c:167:18: warning: implicit declaration of function 'PyString_DecodeEscape' is invalid in C99 [-Wimplicit-function-declaration]
          object = PyString_DecodeEscape(jsondata->ptr+1, len, NULL, 0, NULL);
                   ^
  cjson.c:167:16: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
          object = PyString_DecodeEscape(jsondata->ptr+1, len, NULL, 0, NULL);
                 ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:169:18: warning: implicit declaration of function 'PyString_FromStringAndSize' is invalid in C99 [-Wimplicit-function-declaration]
          object = PyString_FromStringAndSize(jsondata->ptr+1, len);
                   ^
  cjson.c:169:16: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
          object = PyString_FromStringAndSize(jsondata->ptr+1, len);
                 ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:185:39: warning: implicit declaration of function 'PyString_AsString' is invalid in C99 [-Wimplicit-function-declaration]
                               reason ? PyString_AsString(reason) : "bad format");
                                        ^
  cjson.c:185:37: warning: pointer/integer type mismatch in conditional expression ('int' and 'char *') [-Wconditional-type-mismatch]
                               reason ? PyString_AsString(reason) : "bad format");
                                      ^ ~~~~~~~~~~~~~~~~~~~~~~~~~   ~~~~~~~~~~~~
  cjson.c:295:9: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
      str = PyString_FromStringAndSize(jsondata->ptr, ptr - jsondata->ptr);
          ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:300:42: error: too many arguments to function call, expected 1, have 2
          object = PyFloat_FromString(str, NULL);
                   ~~~~~~~~~~~~~~~~~~      ^~~~
  /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/8.1.0/include/stddef.h:105:16: note: expanded from macro 'NULL'
  #  define NULL ((void*)0)
                 ^~~~~~~~~~
  /Users/juanjose.lopez/anaconda/envs/ChevereBot/include/python3.6m/floatobject.h:42:12: note: 'PyFloat_FromString' declared here
  PyAPI_FUNC(PyObject *) PyFloat_FromString(PyObject*);
             ^
  cjson.c:302:18: warning: implicit declaration of function 'PyInt_FromString' is invalid in C99 [-Wimplicit-function-declaration]
          object = PyInt_FromString(PyString_AS_STRING(str), NULL, 10);
                   ^
  cjson.c:302:35: warning: implicit declaration of function 'PyString_AS_STRING' is invalid in C99 [-Wimplicit-function-declaration]
          object = PyInt_FromString(PyString_AS_STRING(str), NULL, 10);
                                    ^
  cjson.c:302:16: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
          object = PyInt_FromString(PyString_AS_STRING(str), NULL, 10);
                 ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:593:14: error: unknown type name 'PyStringObject'
      register PyStringObject* op = (PyStringObject*) string;
               ^
  cjson.c:593:51: error: expected expression
      register PyStringObject* op = (PyStringObject*) string;
                                                    ^
  cjson.c:593:36: error: use of undeclared identifier 'PyStringObject'
      register PyStringObject* op = (PyStringObject*) string;
                                     ^
  cjson.c:602:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
      v = PyString_FromStringAndSize((char *)NULL, newsize);
        ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:614:11: warning: incompatible integer to pointer conversion assigning to 'char *' from 'int' [-Wint-conversion]
          p = PyString_AS_STRING(v);
            ^ ~~~~~~~~~~~~~~~~~~~~~
  cjson.c:646:9: warning: implicit declaration of function '_PyString_Resize' is invalid in C99 [-Wimplicit-function-declaration]
          _PyString_Resize(&v, (int) (p - PyString_AS_STRING(v)));
          ^
  cjson.c:697:10: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
      repr = PyString_FromStringAndSize(NULL, 2 + expandsize*size + 1);
           ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:701:7: warning: incompatible integer to pointer conversion assigning to 'char *' from 'int' [-Wint-conversion]
      p = PyString_AS_STRING(repr);
        ^ ~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:709:57: error: subscripted value is not an array, pointer, or vector
          if ((ch == (Py_UNICODE) PyString_AS_STRING(repr)[0] || ch == '\\')) {
                                  ~~~~~~~~~~~~~~~~~~~~~~~~^~
  cjson.c:804:36: error: subscripted value is not an array, pointer, or vector
      *p++ = PyString_AS_STRING(repr)[0];
             ~~~~~~~~~~~~~~~~~~~~~~~~^~
  cjson.c:828:12: error: no member named 'ob_size' in 'PyTupleObject'
      n = v->ob_size;
          ~  ^
  cjson.c:830:16: warning: implicit declaration of function 'PyString_FromString' is invalid in C99 [-Wimplicit-function-declaration]
          return PyString_FromString("[]");
                 ^
  cjson.c:830:16: warning: incompatible integer to pointer conversion returning 'int' from a function with result type 'PyObject *' (aka 'struct _object *') [-Wint-conversion]
          return PyString_FromString("[]");
                 ^~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:846:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
      s = PyString_FromString("[");
        ^ ~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:850:5: warning: implicit declaration of function 'PyString_ConcatAndDel' is invalid in C99 [-Wimplicit-function-declaration]
      PyString_ConcatAndDel(&s, temp);
      ^
  cjson.c:855:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
      s = PyString_FromString("]");
        ^ ~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:865:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
      s = PyString_FromString(", ");
        ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:868:14: warning: implicit declaration of function '_PyString_Join' is invalid in C99 [-Wimplicit-function-declaration]
      result = _PyString_Join(s, pieces);
               ^
  cjson.c:868:12: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
      result = _PyString_Join(s, pieces);
             ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:902:12: error: no member named 'ob_size' in 'PyListObject'
      if (v->ob_size == 0) {
          ~  ^
  cjson.c:903:16: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
          result = PyString_FromString("[]");
                 ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:913:24: error: no member named 'ob_size' in 'PyListObject'
      for (i = 0; i < v->ob_size; ++i) {
                      ~  ^
  cjson.c:926:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
      s = PyString_FromString("[");
        ^ ~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:935:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
      s = PyString_FromString("]");
        ^ ~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:945:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
      s = PyString_FromString(", ");
        ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:948:12: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
      result = _PyString_Join(s, pieces);
             ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:987:16: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
          result = PyString_FromString("{}");
                 ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:995:11: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
      colon = PyString_FromString(": ");
            ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:1005:14: warning: implicit declaration of function 'PyString_Check' is invalid in C99 [-Wimplicit-function-declaration]
          if (!PyString_Check(key) && !PyUnicode_Check(key)) {
               ^
  cjson.c:1014:9: warning: implicit declaration of function 'PyString_Concat' is invalid in C99 [-Wimplicit-function-declaration]
          PyString_Concat(&s, colon);
          ^
  cjson.c:1027:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
      s = PyString_FromString("{");
        ^ ~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:1036:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
      s = PyString_FromString("}");
        ^ ~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:1046:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
      s = PyString_FromString(", ");
        ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:1049:12: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
      result = _PyString_Join(s, pieces);
             ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:1064:16: warning: incompatible integer to pointer conversion returning 'int' from a function with result type 'PyObject *' (aka 'struct _object *') [-Wint-conversion]
          return PyString_FromString("true");
                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:1066:16: warning: incompatible integer to pointer conversion returning 'int' from a function with result type 'PyObject *' (aka 'struct _object *') [-Wint-conversion]
          return PyString_FromString("false");
                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:1068:16: warning: incompatible integer to pointer conversion returning 'int' from a function with result type 'PyObject *' (aka 'struct _object *') [-Wint-conversion]
          return PyString_FromString("null");
                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:1076:20: warning: incompatible integer to pointer conversion returning 'int' from a function with result type 'PyObject *' (aka 'struct _object *') [-Wint-conversion]
              return PyString_FromString("NaN");
                     ^~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:1079:24: warning: incompatible integer to pointer conversion returning 'int' from a function with result type 'PyObject *' (aka 'struct _object *') [-Wint-conversion]
                  return PyString_FromString("Infinity");
                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:1081:24: warning: incompatible integer to pointer conversion returning 'int' from a function with result type 'PyObject *' (aka 'struct _object *') [-Wint-conversion]
                  return PyString_FromString("-Infinity");
                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:1086:16: warning: implicit declaration of function 'PyInt_Check' is invalid in C99 [-Wimplicit-function-declaration]
      } else if (PyInt_Check(object) || PyLong_Check(object)) {
                 ^
  cjson.c:1149:9: warning: implicit declaration of function 'PyString_AsStringAndSize' is invalid in C99 [-Wimplicit-function-declaration]
      if (PyString_AsStringAndSize(str, &(jsondata.str), NULL) == -1) {
          ^
  cjson.c:1155:35: warning: implicit declaration of function 'PyString_GET_SIZE' is invalid in C99 [-Wimplicit-function-declaration]
      jsondata.end = jsondata.str + PyString_GET_SIZE(str);
                                    ^
  cjson.c:1206:9: warning: implicit declaration of function 'Py_InitModule3' is invalid in C99 [-Wimplicit-function-declaration]
      m = Py_InitModule3("cjson", cjson_methods, module_doc);
          ^
  cjson.c:1206:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
      m = Py_InitModule3("cjson", cjson_methods, module_doc);
        ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  cjson.c:1209:9: error: non-void function 'initcjson' should return a value [-Wreturn-type]
          return;
          ^
  cjson.c:1213:9: error: non-void function 'initcjson' should return a value [-Wreturn-type]
          return;
          ^
  cjson.c:1219:9: error: non-void function 'initcjson' should return a value [-Wreturn-type]
          return;
          ^
  cjson.c:1225:9: error: non-void function 'initcjson' should return a value [-Wreturn-type]
          return;
          ^
  47 warnings and 13 errors generated.
  error: command 'gcc' failed with exit status 1
  
  ----------------------------------------
  Failed building wheel for python-cjson
  Running setup.py clean for python-cjson
Failed to build python-cjson
Installing collected packages: python-cjson
  Running setup.py install for python-cjson ... error
    Complete output from command /Users/juanjose.lopez/anaconda/envs/ChevereBot/bin/python -u -c "import setuptools, tokenize;__file__='/private/var/folders/kn/6ynmt1p91jvdkbv869lkz6vm4c1z19/T/pip-build-guitqjom/python-cjson/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" install --record /var/folders/kn/6ynmt1p91jvdkbv869lkz6vm4c1z19/T/pip-8u5ci1qg-record/install-record.txt --single-version-externally-managed --compile:
    running install
    running build
    running build_ext
    building 'cjson' extension
    creating build
    creating build/temp.macosx-10.7-x86_64-3.6
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -I/Users/juanjose.lopez/anaconda/envs/ChevereBot/include -arch x86_64 -I/Users/juanjose.lopez/anaconda/envs/ChevereBot/include -arch x86_64 -DMODULE_VERSION=1.2.1 -I/Users/juanjose.lopez/anaconda/envs/ChevereBot/include/python3.6m -c cjson.c -o build/temp.macosx-10.7-x86_64-3.6/cjson.o
    cjson.c:167:18: warning: implicit declaration of function 'PyString_DecodeEscape' is invalid in C99 [-Wimplicit-function-declaration]
            object = PyString_DecodeEscape(jsondata->ptr+1, len, NULL, 0, NULL);
                     ^
    cjson.c:167:16: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
            object = PyString_DecodeEscape(jsondata->ptr+1, len, NULL, 0, NULL);
                   ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:169:18: warning: implicit declaration of function 'PyString_FromStringAndSize' is invalid in C99 [-Wimplicit-function-declaration]
            object = PyString_FromStringAndSize(jsondata->ptr+1, len);
                     ^
    cjson.c:169:16: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
            object = PyString_FromStringAndSize(jsondata->ptr+1, len);
                   ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:185:39: warning: implicit declaration of function 'PyString_AsString' is invalid in C99 [-Wimplicit-function-declaration]
                                 reason ? PyString_AsString(reason) : "bad format");
                                          ^
    cjson.c:185:37: warning: pointer/integer type mismatch in conditional expression ('int' and 'char *') [-Wconditional-type-mismatch]
                                 reason ? PyString_AsString(reason) : "bad format");
                                        ^ ~~~~~~~~~~~~~~~~~~~~~~~~~   ~~~~~~~~~~~~
    cjson.c:295:9: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
        str = PyString_FromStringAndSize(jsondata->ptr, ptr - jsondata->ptr);
            ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:300:42: error: too many arguments to function call, expected 1, have 2
            object = PyFloat_FromString(str, NULL);
                     ~~~~~~~~~~~~~~~~~~      ^~~~
    /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/8.1.0/include/stddef.h:105:16: note: expanded from macro 'NULL'
    #  define NULL ((void*)0)
                   ^~~~~~~~~~
    /Users/juanjose.lopez/anaconda/envs/ChevereBot/include/python3.6m/floatobject.h:42:12: note: 'PyFloat_FromString' declared here
    PyAPI_FUNC(PyObject *) PyFloat_FromString(PyObject*);
               ^
    cjson.c:302:18: warning: implicit declaration of function 'PyInt_FromString' is invalid in C99 [-Wimplicit-function-declaration]
            object = PyInt_FromString(PyString_AS_STRING(str), NULL, 10);
                     ^
    cjson.c:302:35: warning: implicit declaration of function 'PyString_AS_STRING' is invalid in C99 [-Wimplicit-function-declaration]
            object = PyInt_FromString(PyString_AS_STRING(str), NULL, 10);
                                      ^
    cjson.c:302:16: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
            object = PyInt_FromString(PyString_AS_STRING(str), NULL, 10);
                   ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:593:14: error: unknown type name 'PyStringObject'
        register PyStringObject* op = (PyStringObject*) string;
                 ^
    cjson.c:593:51: error: expected expression
        register PyStringObject* op = (PyStringObject*) string;
                                                      ^
    cjson.c:593:36: error: use of undeclared identifier 'PyStringObject'
        register PyStringObject* op = (PyStringObject*) string;
                                       ^
    cjson.c:602:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
        v = PyString_FromStringAndSize((char *)NULL, newsize);
          ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:614:11: warning: incompatible integer to pointer conversion assigning to 'char *' from 'int' [-Wint-conversion]
            p = PyString_AS_STRING(v);
              ^ ~~~~~~~~~~~~~~~~~~~~~
    cjson.c:646:9: warning: implicit declaration of function '_PyString_Resize' is invalid in C99 [-Wimplicit-function-declaration]
            _PyString_Resize(&v, (int) (p - PyString_AS_STRING(v)));
            ^
    cjson.c:697:10: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
        repr = PyString_FromStringAndSize(NULL, 2 + expandsize*size + 1);
             ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:701:7: warning: incompatible integer to pointer conversion assigning to 'char *' from 'int' [-Wint-conversion]
        p = PyString_AS_STRING(repr);
          ^ ~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:709:57: error: subscripted value is not an array, pointer, or vector
            if ((ch == (Py_UNICODE) PyString_AS_STRING(repr)[0] || ch == '\\')) {
                                    ~~~~~~~~~~~~~~~~~~~~~~~~^~
    cjson.c:804:36: error: subscripted value is not an array, pointer, or vector
        *p++ = PyString_AS_STRING(repr)[0];
               ~~~~~~~~~~~~~~~~~~~~~~~~^~
    cjson.c:828:12: error: no member named 'ob_size' in 'PyTupleObject'
        n = v->ob_size;
            ~  ^
    cjson.c:830:16: warning: implicit declaration of function 'PyString_FromString' is invalid in C99 [-Wimplicit-function-declaration]
            return PyString_FromString("[]");
                   ^
    cjson.c:830:16: warning: incompatible integer to pointer conversion returning 'int' from a function with result type 'PyObject *' (aka 'struct _object *') [-Wint-conversion]
            return PyString_FromString("[]");
                   ^~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:846:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
        s = PyString_FromString("[");
          ^ ~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:850:5: warning: implicit declaration of function 'PyString_ConcatAndDel' is invalid in C99 [-Wimplicit-function-declaration]
        PyString_ConcatAndDel(&s, temp);
        ^
    cjson.c:855:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
        s = PyString_FromString("]");
          ^ ~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:865:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
        s = PyString_FromString(", ");
          ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:868:14: warning: implicit declaration of function '_PyString_Join' is invalid in C99 [-Wimplicit-function-declaration]
        result = _PyString_Join(s, pieces);
                 ^
    cjson.c:868:12: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
        result = _PyString_Join(s, pieces);
               ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:902:12: error: no member named 'ob_size' in 'PyListObject'
        if (v->ob_size == 0) {
            ~  ^
    cjson.c:903:16: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
            result = PyString_FromString("[]");
                   ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:913:24: error: no member named 'ob_size' in 'PyListObject'
        for (i = 0; i < v->ob_size; ++i) {
                        ~  ^
    cjson.c:926:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
        s = PyString_FromString("[");
          ^ ~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:935:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
        s = PyString_FromString("]");
          ^ ~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:945:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
        s = PyString_FromString(", ");
          ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:948:12: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
        result = _PyString_Join(s, pieces);
               ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:987:16: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
            result = PyString_FromString("{}");
                   ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:995:11: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
        colon = PyString_FromString(": ");
              ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:1005:14: warning: implicit declaration of function 'PyString_Check' is invalid in C99 [-Wimplicit-function-declaration]
            if (!PyString_Check(key) && !PyUnicode_Check(key)) {
                 ^
    cjson.c:1014:9: warning: implicit declaration of function 'PyString_Concat' is invalid in C99 [-Wimplicit-function-declaration]
            PyString_Concat(&s, colon);
            ^
    cjson.c:1027:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
        s = PyString_FromString("{");
          ^ ~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:1036:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
        s = PyString_FromString("}");
          ^ ~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:1046:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
        s = PyString_FromString(", ");
          ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:1049:12: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
        result = _PyString_Join(s, pieces);
               ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:1064:16: warning: incompatible integer to pointer conversion returning 'int' from a function with result type 'PyObject *' (aka 'struct _object *') [-Wint-conversion]
            return PyString_FromString("true");
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:1066:16: warning: incompatible integer to pointer conversion returning 'int' from a function with result type 'PyObject *' (aka 'struct _object *') [-Wint-conversion]
            return PyString_FromString("false");
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:1068:16: warning: incompatible integer to pointer conversion returning 'int' from a function with result type 'PyObject *' (aka 'struct _object *') [-Wint-conversion]
            return PyString_FromString("null");
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:1076:20: warning: incompatible integer to pointer conversion returning 'int' from a function with result type 'PyObject *' (aka 'struct _object *') [-Wint-conversion]
                return PyString_FromString("NaN");
                       ^~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:1079:24: warning: incompatible integer to pointer conversion returning 'int' from a function with result type 'PyObject *' (aka 'struct _object *') [-Wint-conversion]
                    return PyString_FromString("Infinity");
                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:1081:24: warning: incompatible integer to pointer conversion returning 'int' from a function with result type 'PyObject *' (aka 'struct _object *') [-Wint-conversion]
                    return PyString_FromString("-Infinity");
                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:1086:16: warning: implicit declaration of function 'PyInt_Check' is invalid in C99 [-Wimplicit-function-declaration]
        } else if (PyInt_Check(object) || PyLong_Check(object)) {
                   ^
    cjson.c:1149:9: warning: implicit declaration of function 'PyString_AsStringAndSize' is invalid in C99 [-Wimplicit-function-declaration]
        if (PyString_AsStringAndSize(str, &(jsondata.str), NULL) == -1) {
            ^
    cjson.c:1155:35: warning: implicit declaration of function 'PyString_GET_SIZE' is invalid in C99 [-Wimplicit-function-declaration]
        jsondata.end = jsondata.str + PyString_GET_SIZE(str);
                                      ^
    cjson.c:1206:9: warning: implicit declaration of function 'Py_InitModule3' is invalid in C99 [-Wimplicit-function-declaration]
        m = Py_InitModule3("cjson", cjson_methods, module_doc);
            ^
    cjson.c:1206:7: warning: incompatible integer to pointer conversion assigning to 'PyObject *' (aka 'struct _object *') from 'int' [-Wint-conversion]
        m = Py_InitModule3("cjson", cjson_methods, module_doc);
          ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    cjson.c:1209:9: error: non-void function 'initcjson' should return a value [-Wreturn-type]
            return;
            ^
    cjson.c:1213:9: error: non-void function 'initcjson' should return a value [-Wreturn-type]
            return;
            ^
    cjson.c:1219:9: error: non-void function 'initcjson' should return a value [-Wreturn-type]
            return;
            ^
    cjson.c:1225:9: error: non-void function 'initcjson' should return a value [-Wreturn-type]
            return;
            ^
    47 warnings and 13 errors generated.
    error: command 'gcc' failed with exit status 1

[danpascu]

Python 3 is not supported