Fix the previous revision (system header inclusion cleanup), it

doesn't compile on crufty old systems.

src/lib/gen/ioqueue.c

@@ -43,6 +43,7 @@
 #include <stdlib.h>
 #include <string.h>
 #if !defined(_WIN32)
+#include <sys/types.h>
 #include <sys/uio.h>
 #endif
 #include "ioqueue.h"