ftp-ls.c:319:22: error: call to undeclared library function 'strdup' with type 'char *(const char *)'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
                      cur.linkto = xstrdup (p + 4);
                                   ^
--- a/src/ftp-ls.c
+++ b/src/ftp-ls.c
@@ -29,7 +29,7 @@ file, but you are not obligated to do so.  If you do not wish to do
 so, delete this exception statement from your version.  */
 
 #include "config.h"
-#define _XOPEN_SOURCE
+#define _XOPEN_SOURCE 600
 #include <time.h>
 #include <stdio.h>
 #include <stdlib.h>