See https://sourceforge.net/p/pam-python/tickets/5/

--- /tmp/pam-python-1.0.8/src/pam_python.c  2020-11-10 01:58:10.000000000 -0800
+++ pam-python-1.0.8/src/pam_python.c 2021-01-18 09:19:27.082023704 -0800
@@ -104,7 +104,7 @@
 #define	Py23_String_FromStringAndSize PyUnicode_FromStringAndSize
 #define	Py23_String_GET_SIZE	PyUnicode_GET_SIZE
 #define	Py23_String_Parse_Char	"U"
-#define	Py23_String_Size	PyUnicode_Size
+#define	Py23_String_Size	PyBytes_Size
 #define	Py23_String_Type	PyUnicode_Type
 #define	Py23_TYPE(p)		Py_TYPE(p)
 #endif
@@ -434,7 +434,7 @@
    * Just print the exception in some recognisable form, hopefully.
    */
   syslog_open(module_path);
-  if (PyClass_Check(ptype))
+  if (PyType_Check(ptype))
     stype = PyObject_GetAttrString(ptype, "__name__");
   else
   {
@@ -876,7 +876,7 @@
     value = 0;
   else
   {
-    value = Py23_String_AsString(pyValue);
+    value = (char*) Py23_String_AsString(pyValue);
     if (value == 0)
     {
       snprintf(
Only in /home/dan/chroot-cauldron/tmp/pam-python-1.0.8/src: pam_python.so
diff -ru /tmp/pam-python-1.0.8/src/setup.py /home/dan/chroot-cauldron/tmp/pam-python-1.0.8/src/setup.py
--- /tmp/pam-python-1.0.8/src/setup.py  2020-11-10 01:58:10.000000000 -0800
+++ pam-python-1.0.8/src/setup.py 2021-01-18 09:08:21.485867575 -0800
@@ -1,4 +1,4 @@
-#!/usr/bin/python2 -W default
+#!/usr/bin/python3 -W default
 import warnings; warnings.simplefilter('default')

 import distutils.sysconfig
Only in /home/dan/chroot-cauldron/tmp/pam-python-1.0.8/src: test-pam_python.pam
diff -ru /tmp/pam-python-1.0.8/src/test.py /home/dan/chroot-cauldron/tmp/pam-python-1.0.8/src/test.py
--- /tmp/pam-python-1.0.8/src/test.py   2020-11-10 01:58:10.000000000 -0800
+++ pam-python-1.0.8/src/test.py  2021-01-18 09:08:17.370729760 -0800
@@ -1,4 +1,4 @@
-#!/usr/bin/python2 -W default
+#!/usr/bin/python3 -W default
 #
 # This is the test script for libpython-pam.  There aren't many stones
 # left unturned.
diff --git a/pam_python/src/setup.py b/pam_python/src/setup.py
index 38fcddd..496ec6c 100755
--- pam_python/src/setup.py
+++ pam_python/src/setup.py
@@ -38,7 +38,7 @@ ext_modules = [
       include_dirs = [],
       library_dirs=[],
       define_macros=[('LIBPYTHON_SO','"'+libpython_so+'"')] + Py_DEBUG,
-      libraries=["pam","python%d.%d" % sys.version_info[:2]],
+      libraries=["pam","python%d" % sys.version_info[:1]],
     ), ]
 
 setup(