title: Could not compile openssl-sys
body: <p>I added openssl dependency to Cargo.toml.</p>
  
  <pre><code>[dependencies.openssl]
  openssl = "0.2.12"
  </code></pre>
  
  <p>But when I try to build and execute, it cannot compile that crate due to:</p>
  
  <pre><code>type std::sync::mutex::StaticMutexGuard does not implement any method in scope named unwrap
  </code></pre>
  
  <p>Full output:</p>
  
  <pre><code>pablo@boreth:~/pruebas/rust/hello_world$ cargo run --verbose
         Fresh pkg-config v0.1.3
     Compiling openssl-sys v0.2.12
       Running `rustc /home/pablo/.cargo/registry/src/github.com-1ecc6299db9ec823/openssl-sys-0.2.12/src/lib.rs --crate-name openssl-sys --crate-type lib -g -C metadata=e45df04b75965aa1 -C extra-filename=-e45df04b75965aa1 --out-dir /home/pablo/pruebas/rust/hello_world/target/deps --emit=dep-info,link -L /home/pablo/pruebas/rust/hello_world/target/deps -L /home/pablo/pruebas/rust/hello_world/target/deps -Awarnings -L native=/usr/lib/x86_64-linux-gnu -l ssl -l crypto`
  /home/pablo/.cargo/registry/src/github.com-1ecc6299db9ec823/openssl-sys-0.2.12/src/lib.rs:203:54: 203:62 error: type `std::sync::mutex::StaticMutexGuard` does not implement any method in scope named `unwrap`
  /home/pablo/.cargo/registry/src/github.com-1ecc6299db9ec823/openssl-sys-0.2.12/src/lib.rs:203             (*GUARDS)[n as uint] = Some(mutex.lock().unwrap());
                                                                                                                                                     ^~~~~~~~
  /home/pablo/.cargo/registry/src/github.com-1ecc6299db9ec823/openssl-sys-0.2.12/src/lib.rs:214:14: 226:11 error: type `std::sync::once::Once` does not implement any method in scope named `call_once`
  /home/pablo/.cargo/registry/src/github.com-1ecc6299db9ec823/openssl-sys-0.2.12/src/lib.rs:214         INIT.call_once(|| {
  /home/pablo/.cargo/registry/src/github.com-1ecc6299db9ec823/openssl-sys-0.2.12/src/lib.rs:215             SSL_library_init();
  /home/pablo/.cargo/registry/src/github.com-1ecc6299db9ec823/openssl-sys-0.2.12/src/lib.rs:216             SSL_load_error_strings();
  /home/pablo/.cargo/registry/src/github.com-1ecc6299db9ec823/openssl-sys-0.2.12/src/lib.rs:217
  /home/pablo/.cargo/registry/src/github.com-1ecc6299db9ec823/openssl-sys-0.2.12/src/lib.rs:218             let num_locks = CRYPTO_num_locks();
  /home/pablo/.cargo/registry/src/github.com-1ecc6299db9ec823/openssl-sys-0.2.12/src/lib.rs:219             let mutexes = box range(0, num_locks).map(|_| MUTEX_INIT).collect::&lt;Vec&lt;_&gt;&gt;();
                                                                                                ...
  error: aborting due to 2 previous errors
  Could not compile `openssl-sys`.
  
  Caused by:
    Process didn't exit successfully: `rustc /home/pablo/.cargo/registry/src/github.com-1ecc6299db9ec823/openssl-sys-0.2.12/src/lib.rs --crate-name openssl-sys --crate-type lib -g -C metadata=e45df04b75965aa1 -C extra-filename=-e45df04b75965aa1 --out-dir /home/pablo/pruebas/rust/hello_world/target/deps --emit=dep-info,link -L /home/pablo/pruebas/rust/hello_world/target/deps -L /home/pablo/pruebas/rust/hello_world/target/deps -Awarnings -L native=/usr/lib/x86_64-linux-gnu -l ssl -l crypto` (status=101)
  </code></pre>
  
  <p>I'm using Ubuntu Ubuntu 14.04.1 LTS (Trusty Tahr), and I've installed libssl-dev.</p>
  
  <pre><code>pablo@boreth:~$ uname -a
  Linux boreth 3.13.0-43-generic #72-Ubuntu SMP Mon Dec 8 19:35:06 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
  pablo@boreth:~$ dpkg -l libssl-dev
  Deseado=Desconocido/Instalar/Eliminar/Purgar/Retener
  | Estado=No/Instalado/Config-files/Desempaquetado/Medio-conf/Medio-inst/espera-disparo/pendiente-disparo
  |/ Err?=(ninguno)/Requiere-reinst (Estado,Err: mayúsc.=malo)
  ||/ Nombre                                     Versión                    Arquitectura               Descripción
  +++-==========================================-==========================-==========================-=========================================================================================
  ii  libssl-dev:amd64                           1.0.1f-1ubuntu2.7          amd64                      Secure Sockets Layer toolkit - development files
  </code></pre>
  
  <p>rustc and cargo versions:</p>
  
  <pre><code>$ rustc -V
  rustc 0.13.0-nightly (636663172 2014-12-28 16:21:58 +0000)
  $ cargo -V
  cargo 0.0.1-pre-nightly (26ac282 2014-12-30 00:13:39 +0000)
  </code></pre>
  
  <p>Does anyone know a solution or I should wait for an update?</p>