test-threads option is unrecognised

[emixa-d]

When building rust-getopts with tests enabled on Guix, I got the following error message:

Running .guix-tests/smoke

running 1 test
test main ... FAILED

failures:

---- main stdout ----
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: UnrecognizedOption("test-threads")', tests/smoke.rs:7:48
stack backtrace:
   0:     0x7ffff7e4795b - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h190bc4e71a974fd5
   1:     0x7ffff7ea2cfc - core::fmt::write::h5ab597cdd0c00db2
   2:     0x7ffff7e00701 - <unknown>
   3:     0x7ffff7e23c6e - <unknown>
   4:     0x7ffff7e23952 - std::panicking::default_hook::hcffd5d909668cc52
   5:     0x7ffff7e242ae - std::panicking::rust_panic_with_hook::h67db5ff340e389bf
   6:     0x7ffff7e48277 - <unknown>
   7:     0x7ffff7e47a74 - <unknown>
   8:     0x7ffff7e23db2 - rust_begin_unwind
   9:     0x7ffff7df5ff3 - core::panicking::panic_fmt::h4b9cfd185dab4fab
  10:     0x7ffff7df6343 - core::result::unwrap_failed::h1d2e795ba7bc1e45
  11:     0x5555555588f4 - core::result::Result<T,E>::unwrap::hc3c37c10d473db0e
                               at /tmp/guix-build-rust-1.60.0.drv-0/rustc-1.60.0-src/library/core/src/result.rs:1065:23
  12:     0x5555555588f4 - smoke::main::hddc6ec79ca47762a
                               at /tmp/guix-build-rust-getopts-0.2.21.drv-0/getopts-0.2.21/tests/smoke.rs:7:5
  13:     0x5555555588f4 - smoke::main::{{closure}}::h14f4e8f31826c44b
                               at /tmp/guix-build-rust-getopts-0.2.21.drv-0/getopts-0.2.21/tests/smoke.rs:6:1
  14:     0x5555555588f4 - core::ops::function::FnOnce::call_once::hd8dc59dd743cb5eb
                               at /tmp/guix-build-rust-1.60.0.drv-0/rustc-1.60.0-src/library/core/src/ops/function.rs:227:5
  15:     0x7ffff7f68723 - <unknown>
  16:     0x7ffff7f688e4 - <unknown>
  17:     0x7ffff7f5b80d - <unknown>
  18:     0x7ffff7f7cd2f - <unknown>
  19:     0x7ffff7e1c233 - <unknown>
  20:     0x7ffff7bfe3aa - start_thread
  21:     0x7ffff7c7ef7c - clone3
  22:                0x0 - <unknown>


failures:
    main

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

error: in phase 'check': uncaught exception:
%exception #<&invoke-error program: ".guix-tests/smoke" arguments: ("--test-threads" "16") exit-status: 101 term-signal: #f stop-signal: #f> 
phase `check' failed after 0.0 seconds
command ".guix-tests/smoke" "--test-threads" "16" failed with status 101

Looks like --test-threads isn't supported yet.