Require python3 for python bindings

configure.ac

@@ -151,7 +151,7 @@ AC_PROG_MKDIR_P
 
 PKG_PROG_PKG_CONFIG([0.20])
 
-AM_PATH_PYTHON([2.7],, [:])
+AM_PATH_PYTHON([3.8],, [:])
 
 if [test "x$request_lib_only" = "xyes"]; then
   request_app=no
@@ -161,7 +161,7 @@ if [test "x$request_lib_only" = "xyes"]; then
 fi
 
 if [test "x$request_python_bindings" != "xno"]; then
-  AX_PYTHON_DEVEL([>= '2.7'])
+  AX_PYTHON_DEVEL([>= '3.8'])
 fi
 
 if test "x${cython_path}" = "x"; then

python/Makefile.am

@@ -44,6 +44,6 @@ clean-local:
 	-rm -f $(builddir)/nghttp2.c
 
 .pyx.c:
-	$(CYTHON) -o $@ $<
+	$(CYTHON) -3 -o $@ $<
 
 endif # ENABLE_PYTHON_BINDINGS

python/hpackcheck.py

-#!/usr/bin/env python
+#!/usr/bin/env python3
 #
 # This script reads json files given in the command-line (each file
 # must be written in the format described in

python/hpackmake.py

-#!/usr/bin/env python
+#!/usr/bin/env python3
 #
 # This script reads input headers from json file given in the
 # command-line (each file must be written in the format described in

python/nghttp2.pyx

@@ -857,7 +857,7 @@ cdef class _HTTP2SessionCore(_HTTP2SessionCoreBase):
 
         rv = cnghttp2.nghttp2_submit_settings(self.session,
                                               cnghttp2.NGHTTP2_FLAG_NONE,
-                                              iv, sizeof(iv) / sizeof(iv[0]))
+                                              iv, sizeof(iv) // sizeof(iv[0]))
 
         if rv != 0:
             raise Exception('nghttp2_submit_settings failed: {}'.format\
@@ -971,7 +971,7 @@ cdef class _HTTP2ClientSessionCore(_HTTP2SessionCoreBase):
 
         rv = cnghttp2.nghttp2_submit_settings(self.session,
                                               cnghttp2.NGHTTP2_FLAG_NONE,
-                                              iv, sizeof(iv) / sizeof(iv[0]))
+                                              iv, sizeof(iv) // sizeof(iv[0]))
 
         if rv != 0:
             raise Exception('nghttp2_submit_settings failed: {}'.format\