RFR: 8296115: Allow for compiling the JDK with strict standards conformance [v4]

[Magnus Ihse Bursie]

On Wed, 9 Nov 2022 10:26:36 GMT, Daniel Jeliński <djelinski at openjdk.org> wrote:

>> Julian Waters has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains seven additional commits since the last revision:
>> 
>>  - Export not required
>>  - Merge remote-tracking branch 'upstream/master' into permissive
>>  - Merge remote-tracking branch 'upstream/master' into permissive
>>  - Merge remote-tracking branch 'upstream/master' into permissive
>>  - Format
>>  - Keep docs up to date
>>  - New --enable-conforming-compilation option
>
> FWIW, `-permissive-` is getting less permissive with every compiler iteration; with MSVC2022 (` C Compiler:     Version 19.33.31629`) even hotspot doesn't build.

@djelinski That's a bit alarming. :-/ Do you have any idea if it complains "correctly" on Hotspot by detecting fishy code that should be fixed, or if it is overly cranky and is complaining about reasonable but non-standard extensions?

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PR: https://git.openjdk.org/jdk/pull/10912