Cannot build with newest nightly rust

$ rustc --version
rustc 1.5.0-nightly (cff041170 2015-09-17)
$ git clone https://github.com/luqmana/rust-opencl.git
$ cd rust-opencl
$ cargo build --verbose
    Updating registry `https://github.com/rust-lang/crates.io-index`
   Compiling libc v0.1.10
     Running `rustc ~/.cargo/registry/src/github.com-0a35038f75765ae4/libc-0.1.10/rust/src/liblibc/lib.rs --crate-name libc --crate-type lib -g --cfg feature=\"cargo-build\" --cfg feature=\"default\" -C metadata=144c435538abd757 -C extra-filename=-144c435538abd757 --out-dir ~/workspace/rust/rust-opencl/target/debug/deps --emit=dep-info,link -L dependency=~/workspace/rust/rust-opencl/target/debug/deps -L dependency=~/workspace/rust/rust-opencl/target/debug/deps --cap-lints allow`
   Compiling log v0.3.2
     Running `rustc ~/.cargo/registry/src/github.com-0a35038f75765ae4/log-0.3.2/src/lib.rs --crate-name log --crate-type lib -g -C metadata=f18a3e885170bd3f -C extra-filename=-f18a3e885170bd3f --out-dir ~/workspace/rust/rust-opencl/target/debug/deps --emit=dep-info,link -L dependency=~/workspace/rust/rust-opencl/target/debug/deps -L dependency=~/workspace/rust/rust-opencl/target/debug/deps --extern libc=~/workspace/rust/rust-opencl/target/debug/deps/liblibc-144c435538abd757.rlib --cap-lints allow`
   Compiling opencl v0.3.0-dev (file:///~/workspace/rust/rust-opencl)
     Running `rustc src/lib.rs --crate-name opencl --crate-type lib -g --out-dir ~/workspace/rust/rust-opencl/target/debug --emit=dep-info,link -L dependency=~/workspace/rust/rust-opencl/target/debug -L dependency=~/workspace/rust/rust-opencl/target/debug/deps --extern log=~/workspace/rust/rust-opencl/target/debug/deps/liblog-f18a3e885170bd3f.rlib --extern libc=~/workspace/rust/rust-opencl/target/debug/deps/liblibc-144c435538abd757.rlib`
src/ext.rs:67:15: 67:73 error: the trait `core::clone::Clone` is not implemented for the type `extern "C" fn(*mut libc::types::common::c95::c_void, u64, u64, *const cl::cl_image_format, u32, u64, *mut libc::types::common::c95::c_void, *mut u64)` [E0277]
src/ext.rs:67             $(pub $function: (extern fn ($($arg : $arg_type),+) -> $ret)),+
                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/ext.rs:65:24: 65:29 note: in this expansion of #[derive_Clone] (defined in src/ext.rs)
src/ext.rs:20:9: 20:70 note: in this expansion of ext_struct_def! (defined in src/ext.rs)
src/ext.rs:253:5: 263:6 note: in this expansion of cl_extension_loader! (defined in src/ext.rs)
src/ext.rs:67:15: 67:73 help: run `rustc --explain E0277` to see a detailed explanation
src/ext.rs:67:15: 67:73 note: required by `core::clone::Clone::clone`
error: aborting due to previous error
Could not compile `opencl`.

Caused by:
  Process didn't exit successfully: `rustc src/lib.rs --crate-name opencl --crate-type lib -g --out-dir ~/workspace/rust/rust-opencl/target/debug --emit=dep-info,link -L dependency=~/workspace/rust/rust-opencl/target/debug -L dependency=~/workspace/rust/rust-opencl/target/debug/deps --extern log=~/workspace/rust/rust-opencl/target/debug/deps/liblog-f18a3e885170bd3f.rlib --extern libc=~/workspace/rust/rust-opencl/target/debug/deps/liblibc-144c435538abd757.rlib` (exit code: 101)
luqmana / rust-opencl

Cannot build with newest nightly rust #73
