Added #include "string.h" for bzero/FD_ZERO definition on FreeBSD.

src/xpdev/sockwrap.c

@@ -36,6 +36,7 @@
  ****************************************************************************/
 
 #include <stdlib.h>		/* malloc/free on FreeBSD */
+#include <string.h>		/* bzero (for FD_ZERO) on FreeBSD */
 #include <errno.h>		/* ENOMEM */
 #include <stdio.h>		/* SEEK_SET */