OpenCL backend failing to compile

[sug0]

error[E0599]: no method named `raw_os_error` found for enum `std::fs::TryLockError` in the current scope
   --> /home/sugo/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/nam-bellperson-0.26.6-nam.1/src/gpu/locks.rs:178:20
    |
178 |             if err.raw_os_error() == fs2::lock_contended_error().raw_os_error() {
    |                    ^^^^^^^^^^^^ method not found in `std::fs::TryLockError`
    |
note: the method `raw_os_error` exists on the type `std::io::Error`
   --> /home/sugo/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/io/error.rs:716:5
    |
716 |     pub fn raw_os_error(&self) -> Option<RawOsError> {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

For more information about this error, try `rustc --explain E0599`.
error: could not compile `nam-bellperson` (lib) due to 1 previous error
warning: build failed, waiting for other jobs to finish...