[foreign] RFR 8218052: Don't throw an exception when encountering a type with a flexible array member

[Jorn Vernee]

Hi,

 From the bug description:

Currently jextract throws an UnsopportedOpperationException when 
encountering a type that has a flexible array member.

As a result of that no class is written for the type, and when loading 
the enclosing interface this throws a NoClassDefFoundError, prohibiting 
use of the entire header interface.

We could mitigate this problem by emitting an undefined layout reference 
instead of throwing an exception, which would only make the type with 
the flexible array unusable, but still allow other things in the same 
interface to be used.

Please review the following:

Bug: https://bugs.openjdk.java.net/browse/JDK-8218052
Webrev: 
http://cr.openjdk.java.net/~jvernee/panama/webrevs/8218052/webrev.00

Thanks,
Jorn