RFR: 8329257: AIX: Switch HOTSPOT_TOOLCHAIN_TYPE from xlc to gcc [v7]

[Kim Barrett]

On Wed, 10 Apr 2024 12:15:34 GMT, Joachim Kern <jkern at openjdk.org> wrote:

>> As of [JDK-8325880](https://bugs.openjdk.org/browse/JDK-8325880), building the JDK requires version 17 of IBM Open XL C/C++ (xlc). This is in effect clang by another name, and it uses the clang toolchain in the JDK build. Thus the old xlc toolchain was removed by [JDK-8327701](https://bugs.openjdk.org/browse/JDK-8327701).
>> Now we also switch the HOTSPOT_TOOLCHAIN_TYPE from xlc to gcc, removing the last xlc rudiment.
>> This means merging the AIX specific content of utilities/globalDefinitions_xlc.hpp and utilities/compilerWarnings_xlc.hpp into the corresponding gcc files on the on side and removing the defined(TARGET_COMPILER_xlc) blocks in the code, because the defined(TARGET_COMPILER_gcc) blocks work out of the box for the new AIX compiler.
>> The rest of the changes are needed because of using utilities/compilerWarnings_gcc.hpp the compiler is much more nagging about ill formatted printf
>
> Joachim Kern has updated the pull request incrementally with one additional commit since the last revision:
> 
>   saver solution

Looks good.

-------------

Marked as reviewed by kbarrett (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/18536#pullrequestreview-1992964955