diff -r 4b97092aa4bd Modules/readline.c
--- a/Modules/readline.c	Sun Apr 27 18:02:35 2014 +0100
+++ b/Modules/readline.c	Wed Apr 30 11:51:42 2014 +0200
@@ -22,7 +22,7 @@
 #endif
 
 #ifdef SAVE_LOCALE
-#  define RESTORE_LOCALE(sl) { setlocale(LC_CTYPE, sl); free(sl); }
+#  define RESTORE_LOCALE(sl) { if (sl) { setlocale(LC_CTYPE, sl); free(sl); } }
 #else
 #  define RESTORE_LOCALE(sl)
 #endif
@@ -972,9 +972,12 @@ static void
 setup_readline(readlinestate *mod_state)
 {
 #ifdef SAVE_LOCALE
-    char *saved_locale = strdup(setlocale(LC_CTYPE, NULL));
-    if (!saved_locale)
-        Py_FatalError("not enough memory to save locale");
+    char *saved_locale = setlocale(LC_CTYPE, NULL);
+    if (saved_locale != NULL) {
+        saved_locale = strdup(saved_locale);
+        if (!saved_locale)
+            Py_FatalError("not enough memory to save locale");
+    }
 #endif
 
 #ifdef __APPLE__
@@ -1159,10 +1162,13 @@ call_readline(FILE *sys_stdin, FILE *sys
     int signal;
 
 #ifdef SAVE_LOCALE
-    char *saved_locale = strdup(setlocale(LC_CTYPE, NULL));
-    if (!saved_locale)
-        Py_FatalError("not enough memory to save locale");
-    setlocale(LC_CTYPE, "");
+    char *saved_locale = setlocale(LC_CTYPE, NULL);
+    if (saved_locale != NULL) {
+        saved_locale = strdup(saved_locale);
+        if (!saved_locale)
+            Py_FatalError("not enough memory to save locale");
+        setlocale(LC_CTYPE, "");
+    }
 #endif
 
     if (sys_stdin != rl_instream || sys_stdout != rl_outstream) {