[foreign] RFR - JDK-8223033 panama_foreign.md should have a basic hello world example

[Sundararajan Athijegannathan]

* #endif clause missing in header file helloworld.h

* compiler instructions to built shared object is missing (in other 
example, shared object exists already)
Something like:

cc -shared -o helloworld.dylib helloworld.c

* File names may be specified for helloworld.h, helloworld.c (perhaps by 
comment)

-Sundar

On 26/04/19, 8:09 PM, Jim Laskey wrote:
> webrev: http://cr.openjdk.java.net/~jlaskey/8223003/webrev-01
> jbs: https://bugs.openjdk.java.net/browse/JDK-8223033
>