[foreign] RFR 8216484: jextract LayoutUtils has to be modified for Windows

[Jorn Vernee]

Hi,

Continuing from [1, 2]

I have polished the previous patch a little.

Instead of doing the minimum needed for Windows support I've replaced 
all the LayoutUtils.Types constants, and instead am querying the type 
size from libclang and then caching the result, since libclang seems to 
know the right size to use for the platform.

I have been looking at the libclang API and there doesn't seem to be a 
way to specify the target platform. I think it always uses the ABI of 
the platform it was built for.

Bug: https://bugs.openjdk.java.net/browse/JDK-8216484
Updated Webrev: 
http://cr.openjdk.java.net/~jvernee/panama/webrevs/windows_jextract/webrev.01/

Cheers,
Jorn

[1] : 
https://mail.openjdk.java.net/pipermail/panama-dev/2019-January/003680.html
[2] : 
https://mail.openjdk.java.net/pipermail/panama-dev/2019-January/003683.html