rustc -O -o rust main.rs
main.rs:1:1: 1:17 error: unstable feature
main.rs:1 #![feature(tcp)]
^~~~~~~~~~~~~~~~
note: this feature may not be used in the stable release channel
error: aborting due to previous error
make[1]: *** [rust] Error 101
Yes, you must compile using an unstable version of Rust to use unstable features. Stable releases of rust refuse to compile unstable features even if they are supported.
I use Rust 1.0. make fails on it.