module structure for ISA-specific sources and classes

[Magnus Ihse Bursie]

> The JNI code for JFFI, which is shared, can go here as expected:
>    src/java.base/share/native/jdk/internal/ffi/...

Please note that there is a new structure to the "native" directories. 
If the native code is supposed to compile into a libffi.so, the 
directory should be named src/java.base/share/native/libffi, so that 
there is a 1-to-1 match between directory name and the name of the 
native library.

The exception is code which is shared between several libraries, which 
is stored, a bit more ad-hoc, in a suitable subdirectory the 
.../native/common directory.

If you are combining an upstream open source library with some 
additional "wrapping" code, I would suggest creating a library with a 
name distinct from the upstream library, e.g. libjavaffi, and storing 
the upstream source in a separate subdirectory, eg. libjavaffi/libffi. 
This will help the open source community to use a system-installed 
version of the library instead of bundling it.

But then again, I might have misunderstood completely what you're trying 
to achieve. :-)

/Magnus