RFR(S): 8155236: AIX: fix detection of Xrender extension

[Volker Simonis]

Hi,

can somebody please review this AIX-only fix which I've found in one
of my old patch queues :)

http://cr.openjdk.java.net/~simonis/webrevs/2016/8155236/
https://bugs.openjdk.java.net/browse/JDK-8155236

On AIX we have to use a special syntax for the dlopen() string
argument because the shared libraries are packed in multi-architecture
archives. We first try to load the system default libXrender which is
contained in the 'X11.base.lib' fileset starting with AIX 6.1.

If the latter wasn't successful, we also try to load the version under
/opt/freeware. This may be downloaded from the "AIX Toolbox for Linux
Applications" even for AIX 5.3.

Thank you and best regards,
Volker