Make some private symbols static.
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 5575b9f..cb8a1d1 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -3836,7 +3836,7 @@
 "strerror(code) -> string\n\
 Translate an error code to a message string.";
 
-PyObject *
+static PyObject *
 posix_strerror(PyObject *self, PyObject *args)
 {
 	int code;