[Pkg-rust-maintainers] Bug#955997: rust-libc: autopkgtest failure.

[peter green]

Package: rust-libc
Version: 0.22-6-1
Severity: serious

rust-libc's autopkgtest failure is failing, this is happening in both the unstable->testing migration tests and the plain unstable tests and seems to be a blocker for getting rust-cbindgen back into testing.

[libc 0.2.66] thread 'main' panicked at 'const-extern-fn requires a nightly compiler >= 1.40', build.rs:80:13
[libc 0.2.66] stack backtrace:
[libc 0.2.66]    0: backtrace::backtrace::libunwind::trace
[libc 0.2.66]              at /usr/src/rustc-1.41.1/vendor/backtrace/src/backtrace/libunwind.rs:88
[libc 0.2.66]    1: backtrace::backtrace::trace_unsynchronized
[libc 0.2.66]              at /usr/src/rustc-1.41.1/vendor/backtrace/src/backtrace/mod.rs:66
[libc 0.2.66]    2: std::sys_common::backtrace::_print_fmt
[libc 0.2.66]              at src/libstd/sys_common/backtrace.rs:84
[libc 0.2.66]    3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
[libc 0.2.66]              at src/libstd/sys_common/backtrace.rs:61
[libc 0.2.66]    4: core::fmt::write
[libc 0.2.66]              at src/libcore/fmt/mod.rs:1025
[libc 0.2.66]    5: std::io::Write::write_fmt
[libc 0.2.66]              at src/libstd/io/mod.rs:1426
[libc 0.2.66]    6: std::sys_common::backtrace::_print
[libc 0.2.66]              at src/libstd/sys_common/backtrace.rs:65
[libc 0.2.66]    7: std::sys_common::backtrace::print
[libc 0.2.66]              at src/libstd/sys_common/backtrace.rs:50
[libc 0.2.66]    8: std::panicking::default_hook::{{closure}}
[libc 0.2.66]              at src/libstd/panicking.rs:193
[libc 0.2.66]    9: std::panicking::default_hook
[libc 0.2.66]              at src/libstd/panicking.rs:210
[libc 0.2.66]   10: std::panicking::rust_panic_with_hook
[libc 0.2.66]              at src/libstd/panicking.rs:471
[libc 0.2.66]   11: std::panicking::begin_panic
[libc 0.2.66]              at /usr/src/rustc-1.41.1/src/libstd/panicking.rs:404
[libc 0.2.66]   12: build_script_build::main
[libc 0.2.66]              at ./build.rs:80
[libc 0.2.66]   13: std::rt::lang_start::{{closure}}
[libc 0.2.66]              at /usr/src/rustc-1.41.1/src/libstd/rt.rs:67
[libc 0.2.66]   14: std::rt::lang_start_internal::{{closure}}
[libc 0.2.66]              at src/libstd/rt.rs:52
[libc 0.2.66]   15: std::panicking::try::do_call
[libc 0.2.66]              at src/libstd/panicking.rs:292
[libc 0.2.66]   16: __rust_maybe_catch_panic
[libc 0.2.66]              at src/libpanic_unwind/lib.rs:78
[libc 0.2.66]   17: std::panicking::try
[libc 0.2.66]              at src/libstd/panicking.rs:270
[libc 0.2.66]   18: std::panic::catch_unwind
[libc 0.2.66]              at src/libstd/panic.rs:394
[libc 0.2.66]   19: std::rt::lang_start_internal
[libc 0.2.66]              at src/libstd/rt.rs:51
[libc 0.2.66]   20: std::rt::lang_start
[libc 0.2.66]              at /usr/src/rustc-1.41.1/src/libstd/rt.rs:67
[libc 0.2.66]   21: main
[libc 0.2.66]   22: __libc_start_main
[libc 0.2.66]   23: _start
[libc 0.2.66] note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
error: failed to run custom build command for `libc v0.2.66 (/usr/share/cargo/registry/libc-0.2.66)`