Merge pull request #1526 from mbrubeck/lto

Size optimizations: Build with LTO and alloc_system

Cargo.toml

@@ -77,3 +77,7 @@ test = false # no unit tests
 name = "rustup-init"
 path = "src/rustup-cli/main.rs"
 test = false # no unit tests
+
+[profile.release]
+lto = true
+codegen-units = 1

src/rustup-cli/main.rs

@@ -55,12 +55,17 @@ mod term2;
 mod errors;
 mod help;
 
+use std::alloc::System;
 use std::env;
 use std::path::PathBuf;
 use errors::*;
 use rustup_dist::dist::TargetTriple;
 use rustup::env_var::RUST_RECURSION_COUNT_MAX;
 
+// Always use the system allocator, to reduce binary size.
+#[global_allocator]
+static _ALLOCATOR: System = System;
+
 fn main() {
     if let Err(ref e) = run_rustup() {
         common::report_error(e);