Fix some Py_ssize_t warnings on Win64 that were probably bugs

Objects/bytesobject.c

@@ -108,7 +108,7 @@ PyObject *
 PyBytes_FromStringAndSize(const char *bytes, Py_ssize_t size)
 {
     PyBytesObject *new;
-    int alloc;
+    Py_ssize_t alloc;
 
     assert(size >= 0);
 
@@ -1458,7 +1458,7 @@ return_self(PyBytesObject *self)
 }
 
 Py_LOCAL_INLINE(Py_ssize_t)
-countchar(const char *target, int target_len, char c, Py_ssize_t maxcount)
+countchar(const char *target, Py_ssize_t target_len, char c, Py_ssize_t maxcount)
 {
     Py_ssize_t count=0;
     const char *start=target;

Objects/memoryobject.c

@@ -78,7 +78,7 @@ memory_new(PyTypeObject *subtype, PyObject *args, PyObject *kwds)
 
 static void
 _strided_copy_nd(char *dest, char *src, int nd, Py_ssize_t *shape,
-                 Py_ssize_t *strides, int itemsize, char fort)
+                 Py_ssize_t *strides, Py_ssize_t itemsize, char fort)
 {
         int k;
         Py_ssize_t outstride;
@@ -298,7 +298,7 @@ memory_format_get(PyMemoryViewObject *self)
 static PyObject *
 memory_itemsize_get(PyMemoryViewObject *self)
 {
-        return PyInt_FromLong(self->view.itemsize);
+        return PyInt_FromSsize_t(self->view.itemsize);
 }
 
 static PyObject *