`libgit2-sys::git_error` must implement `core::kinds::Send`

[akosthekiss]

When building cargo for aarch64 with a recent self-built rustc, I get the following error for git2:

"/home/akiss/opt/rust-aarch64-latest/bin/rustc" -V
rustc 0.13.0-dev (539d2ac4b 2014-12-27 21:37:09 +0100)
/home/akiss/opt/cargo-aarch64-latest/bin/cargo build --target aarch64-unknown-linux-gnu  
   Compiling git2 v0.1.3
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:100:1: 106:2 error: the trait `core::kinds::Send` is not implemented for the type `*mut u8`
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:100 impl error::Error for Error {
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:101     fn description(&self) -> &str {
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:102         unsafe { str::from_c_str(self.raw.message as *const _) }
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:103     }
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:104 
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:105     fn detail(&self) -> Option<String> { Some(self.message()) }
                                                                                        ...
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:100:1: 106:2 note: the type `*mut u8` must implement `core::kinds::Send` because it appears within the type `libgit2-sys::git_error`
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:100 impl error::Error for Error {
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:101     fn description(&self) -> &str {
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:102         unsafe { str::from_c_str(self.raw.message as *const _) }
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:103     }
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:104 
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:105     fn detail(&self) -> Option<String> { Some(self.message()) }
                                                                                        ...
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:100:1: 106:2 note: the type `libgit2-sys::git_error` must implement `core::kinds::Send` because it appears within the type `error::Error`
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:100 impl error::Error for Error {
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:101     fn description(&self) -> &str {
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:102         unsafe { str::from_c_str(self.raw.message as *const _) }
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:103     }
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:104 
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:105     fn detail(&self) -> Option<String> { Some(self.message()) }
                                                                                        ...
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:100:1: 106:2 note: the trait `core::kinds::Send` must be implemented because it is required by `std::error::Error`
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:100 impl error::Error for Error {
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:101     fn description(&self) -> &str {
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:102         unsafe { str::from_c_str(self.raw.message as *const _) }
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:103     }
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:104 
/home/akiss/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.1.3/src/error.rs:105     fn detail(&self) -> Option<String> { Some(self.message()) }
                                                                                        ...
error: aborting due to previous error
Could not compile `git2`.

The error is actually reported against *mut c_char (c_char is u8 on aarch64) but it seemed to me that the note (i.e., "type libgit2-sys::git_error must implement core::kinds::Send because it appears within the type error::Error") is more relevant here.