RFR(S): 8026487 : PPC64: Implement 'os::fork_and_exec' on AIX

[Volker Simonis]

Hi,

could you please review the following webrev:

http://cr.openjdk.java.net/~simonis/webrevs/8026487/

for bug:

https://bugs.openjdk.java.net/browse/JDK-8026487

which only touches the AIX specific file src/os/aix/vm/os_aix.cpp.

Here's some background:

During testing with the OpenJDK regression tests we realized that
we've omitted the implementation of os::fork_and_exec() on AIX. This
method is only required by the options -XX:OnOutOfMemoryError,
-XX:OnError and -XX:+ShowMessageBoxOnError if the user answers with
'yes'.

The implementation is a straightforward adaptation of the
corresponding Linux code.

This change also contains the trivial implementation of
os::Aix::available_memory() which is only used by the trace macro
RC_TRACE_WITH_THREAD in VM_RedefineClasses. The implementation simply
calls os::Aix::get_meminfo() which had been already implemented
before.

Regards,
Volker