simple-rust-tests/__ffi/c_export

Rust libray build:

cargo build

Python test:

python call_in_python.py

C test:

gcc call_in_c.c -L target/debug/ -lstringtools

NodeJS test:

npm install ffi
node call_in_node.js

Reference: http://siciarz.net/24-days-of-rust-calling-rust-from-other-languages/