Experiment with and document building native library

[borkdude]

https://github.com/oracle/graal/blob/master/substratevm/ImplementingNativeMethodsInJavaWithSVM.md

[borkdude]

This has been done in the form of https://github.com/borkdude/sci/blob/master/doc/libsci.md.

[borkdude]

Hmm, I guess we could still dedicate some text to this maybe.