[foreign-jextract] RFR 8236434: Initial jextract API implementation

[Maurizio Cimadamore]

Pushed, with some updates following offline discussion with Jorn:

* update Copyright
* consolidated platform dependent constants between ClangLayouts (now 
removed) and LayoutUtils

Maurizio

On 06/01/2020 12:31, Maurizio Cimadamore wrote:
>
> On 06/01/2020 12:00, sundararajan.athijegannathan at oracle.com wrote:
>> This review is response to 
>> https://mail.openjdk.java.net/pipermail/panama-dev/2019-December/006905.html
>>
>> I did quick review. Also checked build/test on Mac OS. All fine.
>>
>> * File: ClangUtils (preexisting code). This code caches stuff as 
>> static fields and so won't allow proper "instancing" of clang 
>> artifacts across jextract tasks for example. Besides plan is to 
>> handle Atomic by modification of libclang, right? Do we want this in 
>> the new code?
>
> We can definitively drop these for now. A better approach is to patch 
> libclang to expose the correct info.
>
>>
>> * File: src/jdk.incubator.jextract/share/classes/module-info.java
>>
>> copyright is missing
>
> Oops
>
> Thanks
> Maurizio
>
>>
>> -Sundar
>>
>>
>>