Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

vendor/scopeguard/examples/readme.rs

@@ -0,0 +1,29 @@
+#[macro_use(defer)]
+extern crate scopeguard;
+
+use scopeguard::guard;
+
+fn f() {
+    defer! {
+        println!("Called at return or panic");
+    }
+    panic!();
+}
+
+use std::fs::File;
+use std::io::Write;
+
+fn g() {
+    let f = File::create("newfile.txt").unwrap();
+    let mut file = guard(f, |f| {
+        // write file at return or panic
+        let _ = f.sync_all();
+    });
+    // access the file through the scope guard itself
+    file.write_all(b"test me\n").unwrap();
+}
+
+fn main() {
+    f();
+    g();
+}