Fix several internal function signatures and function pointer casts that lead to warnings in gcc-8.

Cython/Utility/CythonFunction.c

@@ -340,7 +340,7 @@ __Pyx_CyFunction_get_kwdefaults(__pyx_CyFunctionObject *op, CYTHON_UNUSED void *
 }
 
 static int
-__Pyx_CyFunction_set_annotations(__pyx_CyFunctionObject *op, PyObject* value) {
+__Pyx_CyFunction_set_annotations(__pyx_CyFunctionObject *op, PyObject* value, CYTHON_UNUSED void *context) {
     PyObject* tmp;
     if (!value || value == Py_None) {
         value = NULL;

Cython/Utility/ObjectHandling.c

@@ -1575,11 +1575,11 @@ static PyObject* __Pyx__CallUnboundCMethod0(__Pyx_CachedCFunction* cfunc, PyObje
         (likely((cfunc)->flag == METH_NOARGS) ?  (*((cfunc)->func))(self, NULL) : \
          (PY_VERSION_HEX >= 0x030600B1 && likely((cfunc)->flag == METH_FASTCALL) ? \
             (PY_VERSION_HEX >= 0x030700A0 ? \
-                (*(__Pyx_PyCFunctionFast)(cfunc)->func)(self, &$empty_tuple, 0) : \
-                (*(__Pyx_PyCFunctionFastWithKeywords)(cfunc)->func)(self, &$empty_tuple, 0, NULL)) : \
+                (*(__Pyx_PyCFunctionFast)(void*)(PyCFunction)(cfunc)->func)(self, &$empty_tuple, 0) : \
+                (*(__Pyx_PyCFunctionFastWithKeywords)(void*)(PyCFunction)(cfunc)->func)(self, &$empty_tuple, 0, NULL)) : \
           (PY_VERSION_HEX >= 0x030700A0 && (cfunc)->flag == (METH_FASTCALL | METH_KEYWORDS) ? \
-            (*(__Pyx_PyCFunctionFastWithKeywords)(cfunc)->func)(self, &$empty_tuple, 0, NULL) : \
-            (likely((cfunc)->flag == (METH_VARARGS | METH_KEYWORDS)) ?  ((*(PyCFunctionWithKeywords)(cfunc)->func)(self, $empty_tuple, NULL)) : \
+            (*(__Pyx_PyCFunctionFastWithKeywords)(void*)(PyCFunction)(cfunc)->func)(self, &$empty_tuple, 0, NULL) : \
+            (likely((cfunc)->flag == (METH_VARARGS | METH_KEYWORDS)) ?  ((*(PyCFunctionWithKeywords)(void*)(PyCFunction)(cfunc)->func)(self, $empty_tuple, NULL)) : \
                ((cfunc)->flag == METH_VARARGS ?  (*((cfunc)->func))(self, $empty_tuple) : \
                __Pyx__CallUnboundCMethod0(cfunc, self)))))) : \
         __Pyx__CallUnboundCMethod0(cfunc, self))
@@ -1633,12 +1633,12 @@ static CYTHON_INLINE PyObject* __Pyx_CallUnboundCMethod1(__Pyx_CachedCFunction*
             return (*(cfunc->func))(self, arg);
         } else if (PY_VERSION_HEX >= 0x030600B1 && flag == METH_FASTCALL) {
             if (PY_VERSION_HEX >= 0x030700A0) {
-                return (*(__Pyx_PyCFunctionFast)cfunc->func)(self, &arg, 1);
+                return (*(__Pyx_PyCFunctionFast)(void*)(PyCFunction)cfunc->func)(self, &arg, 1);
             } else {
-                return (*(__Pyx_PyCFunctionFastWithKeywords)cfunc->func)(self, &arg, 1, NULL);
+                return (*(__Pyx_PyCFunctionFastWithKeywords)(void*)(PyCFunction)cfunc->func)(self, &arg, 1, NULL);
             }
         } else if (PY_VERSION_HEX >= 0x030700A0 && flag == (METH_FASTCALL | METH_KEYWORDS)) {
-            return (*(__Pyx_PyCFunctionFastWithKeywords)cfunc->func)(self, &arg, 1, NULL);
+            return (*(__Pyx_PyCFunctionFastWithKeywords)(void*)(PyCFunction)cfunc->func)(self, &arg, 1, NULL);
         }
     }
     return __Pyx__CallUnboundCMethod1(cfunc, self, arg);
@@ -1655,7 +1655,7 @@ static PyObject* __Pyx__CallUnboundCMethod1(__Pyx_CachedCFunction* cfunc, PyObje
         Py_INCREF(arg);
         PyTuple_SET_ITEM(args, 0, arg);
         if (cfunc->flag & METH_KEYWORDS)
-            result = (*(PyCFunctionWithKeywords)cfunc->func)(self, args, NULL);
+            result = (*(PyCFunctionWithKeywords)(void*)(PyCFunction)cfunc->func)(self, args, NULL);
         else
             result = (*cfunc->func)(self, args);
     } else {
@@ -1698,14 +1698,14 @@ static CYTHON_INLINE PyObject *__Pyx_CallUnboundCMethod2(__Pyx_CachedCFunction *
         PyObject *args[2] = {arg1, arg2};
         if (cfunc->flag == METH_FASTCALL) {
             #if PY_VERSION_HEX >= 0x030700A0
-            return (*(__Pyx_PyCFunctionFast)cfunc->func)(self, args, 2);
+            return (*(__Pyx_PyCFunctionFast)(void*)(PyCFunction)cfunc->func)(self, args, 2);
             #else
-            return (*(__Pyx_PyCFunctionFastWithKeywords)cfunc->func)(self, args, 2, NULL);
+            return (*(__Pyx_PyCFunctionFastWithKeywords)(void*)(PyCFunction)cfunc->func)(self, args, 2, NULL);
             #endif
         }
         #if PY_VERSION_HEX >= 0x030700A0
         if (cfunc->flag == (METH_FASTCALL | METH_KEYWORDS))
-            return (*(__Pyx_PyCFunctionFastWithKeywords)cfunc->func)(self, args, 2, NULL);
+            return (*(__Pyx_PyCFunctionFastWithKeywords)(void*)(PyCFunction)cfunc->func)(self, args, 2, NULL);
         #endif
     }
     return __Pyx__CallUnboundCMethod2(cfunc, self, arg1, arg2);
@@ -1724,7 +1724,7 @@ static PyObject* __Pyx__CallUnboundCMethod2(__Pyx_CachedCFunction* cfunc, PyObje
         Py_INCREF(arg2);
         PyTuple_SET_ITEM(args, 1, arg2);
         if (cfunc->flag & METH_KEYWORDS)
-            result = (*(PyCFunctionWithKeywords)cfunc->func)(self, args, NULL);
+            result = (*(PyCFunctionWithKeywords)(void*)(PyCFunction)cfunc->func)(self, args, NULL);
         else
             result = (*cfunc->func)(self, args);
     } else {
@@ -2121,9 +2121,9 @@ static CYTHON_INLINE PyObject * __Pyx_PyCFunction_FastCall(PyObject *func_obj, P
     assert(!PyErr_Occurred());
 
     if ((PY_VERSION_HEX < 0x030700A0) || unlikely(flags & METH_KEYWORDS)) {
-        return (*((__Pyx_PyCFunctionFastWithKeywords)meth)) (self, args, nargs, NULL);
+        return (*((__Pyx_PyCFunctionFastWithKeywords)(void*)meth)) (self, args, nargs, NULL);
     } else {
-        return (*((__Pyx_PyCFunctionFast)meth)) (self, args, nargs);
+        return (*((__Pyx_PyCFunctionFast)(void*)meth)) (self, args, nargs);
     }
 }
 #endif  /* CYTHON_FAST_PYCCALL */