https://github.com/nurse/nkf/commit/8246108073f739d45a21ef42ad2d9342fa3c6c28

From 8246108073f739d45a21ef42ad2d9342fa3c6c28 Mon Sep 17 00:00:00 2001
From: slic <slic-io@users.noreply.github.com>
Date: Sun, 6 Mar 2022 18:05:54 +0900
Subject: [PATCH] fix: python3 extention ABI # variant when parsing warning

--- a/NKF.python3/NKF_python.c
+++ b/NKF.python3/NKF_python.c
@@ -20,6 +20,8 @@ Changes.
 **    THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE.
 ***************************************************************************/
 
+#define PY_SSIZE_T_CLEAN
+
 #include "Python.h"
 #include <setjmp.h>
 
@@ -33,7 +35,7 @@ Changes.
 #undef FALSE
 #define putchar(c)      pynkf_putchar(c)
 
-static int pynkf_ibufsize, pynkf_obufsize;
+static Py_ssize_t pynkf_ibufsize, pynkf_obufsize;
 static unsigned char *pynkf_inbuf, *pynkf_outbuf;
 static int pynkf_icount,pynkf_ocount;
 static unsigned char *pynkf_iptr, *pynkf_optr;
@@ -62,7 +64,7 @@ pynkf_ungetc(int c, FILE *f)
 static void
 pynkf_putchar(int c)
 {
-  size_t size;
+  Py_ssize_t size;
   unsigned char *p;
 
   if (pynkf_guess_flag) {
@@ -89,7 +91,7 @@ pynkf_putchar(int c)
 #include "../nkf.c"
 
 static PyObject *
-pynkf_convert(unsigned char* str, int strlen, char* opts, int optslen)
+pynkf_convert(unsigned char* str, Py_ssize_t strlen, char* opts, Py_ssize_t optslen)
 {
   PyObject * res;
 
@@ -157,12 +159,12 @@ static
 PyObject *pynkf_nkf(PyObject *self, PyObject *args)
 {
   unsigned char *str;
-  int strlen;
+  Py_ssize_t strlen;
   char *opts;
-  int optslen;
+  Py_ssize_t optslen;
   PyObject* res;
 
-  if (!PyArg_ParseTuple(args, "s#y#", &opts, &optslen, &str, &strlen)) {
+  if (!PyArg_ParseTuple(args, "s#s#", &opts, &optslen, &str, &strlen)) {
     return NULL;
   }
   res = pynkf_convert(str, strlen, opts, optslen);
@@ -178,7 +180,7 @@ PyObject *pynkf_guess(PyObject *self, PyObject *args)
   int strlen;
   PyObject* res;
 
-  if (!PyArg_ParseTuple(args, "y#", &str, &strlen)) {
+  if (!PyArg_ParseTuple(args, "s#", &str, &strlen)) {
     return NULL;
   }
   res = pynkf_convert_guess(str, strlen);