RFR: 8204541: Correctly support AIX xlC 16.1 symbol visibility flags [v2]

[Kim Barrett]

> On Mar 18, 2022, at 4:11 AM, Thomas Stuefe <stuefe at openjdk.java.net> wrote:
> 
> On Fri, 18 Mar 2022 08:03:11 GMT, Ichiroh Takiguchi <itakiguchi at openjdk.org> wrote:
> 
>>> This change is just for AIX platform with IBM XL C/C++ 16.1.
>>> By this change, lib's entry points are reduced by compilation and linkage option changes.
>>> 
>>> Without changes:
>>> 
>>> $ dump -X32_64 -Tv lib/libawt.so | grep EXP | wc
>>> 914
>>> 
>>> With changes
>>> 
>>> $ dump -X32_64 -Tv lib/libawt.so | grep EXP | wc
>>> 142
>> 
>> Ichiroh Takiguchi has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>  Remove unexpected comment
> 
> So, does this mean we cannot build with older xlC versions anymore? Just curious.

XLC16 (xlclang/xlclang++) is needed for C++11/14 support; the older versions
of XLC don't support the newer language standards.  So XLC16 is required for
for JDK16+.

> Pinging @backwaterred .
> 
> -------------
> 
> PR: https://git.openjdk.java.net/jdk/pull/7862