Drop size optimizations that require nightly builds

Cargo.toml

@@ -15,7 +15,6 @@ panic = "abort"
 
 [profile.release]
 lto = true
-opt-level = "s"
 panic = "abort"
 
 [dependencies]

src/main.rs

@@ -1,6 +1,4 @@
 #![feature(process_exec)]
-#![feature(alloc_system)]
-extern crate alloc_system;
 
 #[macro_use]
 extern crate clap;