Issue #19884, readline: calling rl_variable_bind ("enable-meta-key", "off")

does crash on Mac OS X which uses libedit instead of readline.

Modules/readline.c

@@ -933,15 +933,19 @@ setup_readline(void)
     begidx = PyInt_FromLong(0L);
     endidx = PyInt_FromLong(0L);
 
+#ifndef __APPLE__
     if (!isatty(STDOUT_FILENO)) {
         /* Issue #19884: stdout is no a terminal. Disable meta modifier
            keys to not write the ANSI sequence "\033[1034h" into stdout. On
            terminals supporting 8 bit characters like TERM=xterm-256color
            (which is now the default Fedora since Fedora 18), the meta key is
            used to enable support of 8 bit characters (ANSI sequence
-           "\033[1034h"). */
+           "\033[1034h").
+
+           With libedit, this call makes readline() crash. */
         rl_variable_bind ("enable-meta-key", "off");
     }
+#endif
 
     /* Initialize (allows .inputrc to override)
      *