added missing header for close() in VxWorks 6.3

modules/libcom/src/osi/os/vxWorks/osdFindSymbol.c

@@ -20,6 +20,7 @@
 #include <fcntl.h>
 #include <unistd.h>
 #include <loadLib.h>
+#include <ioLib.h>
 
 #include "dbmf.h"
 #include "epicsString.h"