Some platforms have rl_completion_append_character but not rl_completion_suppress_append.
Reported by Mark D.
diff --git a/Modules/readline.c b/Modules/readline.c
index cd79cc6..2db6cfb 100644
--- a/Modules/readline.c
+++ b/Modules/readline.c
@@ -803,6 +803,8 @@
 {
 #ifdef HAVE_RL_COMPLETION_APPEND_CHARACTER
 	rl_completion_append_character ='\0';
+#endif
+#ifdef HAVE_RL_COMPLETION_SUPPRESS_APPEND
 	rl_completion_suppress_append = 0;
 #endif
 	Py_XDECREF(begidx);