This is a follow up change of JDK-8196516 which discovered that on AIX libfontmanager is always linked against libawt_headless at build time. If we are running in a headfull environemnt, libfontmanager will dynamically load libawt_xawt which is not good because libawt_headless and libawt_xawt define some common symbols. If we're running in a headless environment, libawt_headless may be loaded a second time (at least on Linux/Solaris) which isn't good either.

Both of these scenarios haven't caused any problems on AIX yet, but I think it's good to cleanup the AIX implementation as well and don't link libfontmanager against libawt_headless anymore. In order to achieve this, we have to allow unresolved symbols during the linking of libfontmanager. This can be easily achieved by adding the additions linker flag "-Wl$(COMMA)-berok" through LDFLAGS_aix.