Signed-off-by: Rob Browning <rlb@defaultvalue.org>
#include <time.h>
#endif
-#ifdef BUP_HAVE_READLINE
-#if ! defined(_XOPEN_SOURCE) || _XOPEN_SOURCE < BUP_RL_EXPECTED_XOPEN_SOURCE
-# warning "_XOPEN_SOURCE version is too low for readline"
+#if defined(BUP_RL_EXPECTED_XOPEN_SOURCE) \
+ && (!defined(_XOPEN_SOURCE) || _XOPEN_SOURCE < BUP_RL_EXPECTED_XOPEN_SOURCE)
+# warning "_XOPEN_SOURCE version is incorrect for readline"
#endif
+
+#ifdef BUP_HAVE_READLINE
#include <readline/readline.h>
#include <readline/history.h>
#endif