RFR[9](XS): 8035876: AIX: Fix AIX build after '8034174: Remove use of JVM_* functions from java.net code'

[Volker Simonis]

Hi,

first of all I know that I have to blame myself for not subscribing to
the net-dev list (I thought I was but there are much too many lists to
really keep track:)

Nevertheless I would like to kindly ask everybody who changes AIX
related stuff (as it was done in '8034174: Remove use of JVM_*
functions from java.net code') to also cross-post to
"ppc-aix-port-dev at openjdk.java.net". This really makes it easier for
us to maintain the port.

That said, '8034174: Remove use of JVM_* functions from java.net code'
broke the AIX build and here's the small change which fixes it again:

http://cr.openjdk.java.net/~simonis/webrevs/8035876/
https://bugs.openjdk.java.net/browse/JDK-8035876

- The first problem is the we need to include <sys/ioctl.h> on AIX as
well in 'net_util_md.c' after NET_SocketAvailable was added to the
file which uses an FIONREAD ioctl call.

- The second problem is a little more tricky. Before 8034174,
'net_util_md.h' conditionally declared one of NET_Select or NET_Poll,
depending on the value of the USE_SELECT macro:

  65 #ifdef USE_SELECT
  66 extern int NET_Select(int s, fd_set *readfds, fd_set *writefds,
  67                fd_set *exceptfds, struct timeval *timeout);
  68 #else
  69 extern int NET_Poll(struct pollfd *ufds, unsigned int nfds, int timeout);
  70 #endif

After the change, both are defined unconditionally, which I think was
an oversight and does not work on AIX.
In this change I have restored the old behaviour, which should still
work on all platforms.

But in general, I looked a little closer at the problem and found that
USE_SELECT isn't defined anywhere in the make files. So it's usage in
the source files is redundant (because it is always undefined) and
could be removed. I'd prefer to clean this up in a separate follow-up
change but if somebody really  wants, I could also put it in this
webrev.

Thank you and best regards,
Volker