RFR: 8237830: support O_CLOEXEC in os::open on other OS than Linux

[Baesken, Matthias]

Hello, please review my change that adds O_CLOEXEC  in HS os::open  for AIX and BSD/macOS .

Change

https://bugs.openjdk.java.net/browse/JDK-8043780

introduced the usage of O_CLOEXEC in os::open on Linux.

We might do the same on other UNIX OS for example BSD/Mac and AIX (AIX 7.X  has  O_CLOEXEC).


Bug/webrev :

https://bugs.openjdk.java.net/browse/JDK-8237830

http://cr.openjdk.java.net/~mbaesken/webrevs/8237830.0/

Thanks, Matthias