Add rust package

packages/rust.rb

+require 'package'
+
+class Rust < Package
+  description 'Rust is a systems programming language that runs blazingly fast, prevents segfaults, and guarantees thread safety.'
+  homepage 'https://www.rust-lang.org/'
+  version '1.23.0'
+  source_url 'https://raw.githubusercontent.com/rust-lang/rust/1.23.0/RELEASES.md'
+  source_sha256 '05a4f35bad7643aea094066815cf856009b115170086bbd916cfb0ee9a31f54e'
+
+  binary_url ({
+  })
+  binary_sha256 ({
+  })
+
+  def self.install
+    if ARCH == 'armv7l'
+      default_host = "armv7-unknown-linux-gnueabihf"
+    else
+      default_host = "#{ARCH}-unknown-linux-gnu"
+    end
+    system "curl -Ls https://sh.rustup.rs -o rust.sh"
+    system "sed -i 's,\$(mktemp -d 2>/dev/null || ensure mktemp -d -t rustup),#{CREW_DEST_DIR},' rust.sh"
+    system "bash rust.sh -y --no-modify-path --default-host #{default_host} --default-toolchain stable"
+    system "mkdir -p #{CREW_DEST_DIR}/$HOME"
+    system "mkdir -p #{CREW_DEST_PREFIX}/bin"
+    system "mkdir -p #{CREW_DEST_PREFIX}/share/cargo"
+    system "mkdir -p #{CREW_DEST_PREFIX}/share/rustup"
+    system "cp -r ~/.cargo/. #{CREW_DEST_PREFIX}/share/cargo"
+    system "cp -r ~/.rustup/. #{CREW_DEST_PREFIX}/share/rustup"
+    FileUtils.cd("#{CREW_DEST_PREFIX}/share/cargo/bin") do
+      system "find . -type f -exec ln -s #{CREW_PREFIX}/share/cargo/bin/{} #{CREW_DEST_PREFIX}/bin \\;"
+    end
+    system "rm -rf ~/.cargo ~/.rustup"
+    system "ln -s #{CREW_PREFIX}/share/cargo $HOME/.cargo"
+    system "ln -s #{CREW_PREFIX}/share/rustup $HOME/.rustup"
+    system "ln -s #{CREW_PREFIX}/share/cargo #{CREW_DEST_DIR}/$HOME/.cargo"
+    system "ln -s #{CREW_PREFIX}/share/rustup #{CREW_DEST_DIR}/$HOME/.rustup"
+  end
+end