move pygetopt.h to internal (closes bpo-32264) (#4830)

diff --git a/Include/internal/pygetopt.h b/Include/internal/pygetopt.h
new file mode 100644
index 0000000..df6f183
--- /dev/null
+++ b/Include/internal/pygetopt.h
@@ -0,0 +1,19 @@
+#ifndef Py_INTERNAL_PYGETOPT_H
+#define Py_INTERNAL_PYGETOPT_H
+
+int _PyOS_opterr;
+int _PyOS_optind;
+wchar_t *_PyOS_optarg;
+
+void _PyOS_ResetGetOpt(void);
+
+typedef struct {
+    const wchar_t *name;
+    int has_arg;
+    int val;
+} _PyOS_LongOption;
+
+int _PyOS_GetOpt(int argc, wchar_t **argv, wchar_t *optstring,
+                 const _PyOS_LongOption *longopts, int *longindex);
+
+#endif /* !Py_INTERNAL_PYGETOPT_H */