diff --git a/Modules/readline.c b/Modules/readline.c
index 705d766b970..a3dc4d9785b 100644
--- a/Modules/readline.c
+++ b/Modules/readline.c
@@ -38,9 +38,12 @@
 #if defined(_RL_FUNCTION_TYPEDEF)
 extern char **completion_matches(char *, rl_compentry_func_t *);
 #else
+
+#if !defined(__APPLE__)
 extern char **completion_matches(char *, CPFunction *);
 #endif
 #endif
+#endif
 
 #ifdef __APPLE__
 /*