5880 Increase IOV_MAX to at least 1024
Portions contributed by: Jerry Jelinek <jerry.jelinek@joyent.com>

@@ -21,10 +21,11 @@
 
 /*
  * Copyright (c) 1995, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright 2016 Nexenta Systems, Inc.  All rights reserved.
  * Copyright 2019 OmniOS Community Edition (OmniOSce) Association.
+ * Copyright 2015, Joyent, Inc. All rights reserved.
  */
 
 #include <sys/types.h>
 #include <sys/t_lock.h>
 #include <sys/param.h>

@@ -1885,11 +1886,11 @@
 
 ssize_t
 soreadfile(file_t *fp, uchar_t *buf, u_offset_t fileoff, int *err, size_t size)
 {
         struct uio auio;
-        struct iovec aiov[MSG_MAXIOVLEN];
+        struct iovec aiov[1];
         register vnode_t *vp;
         int ioflag, rwflag;
         ssize_t cnt;
         int error = 0;
         int iovcnt = 0;