rust problem when building firefox

[Thomas Klausner <wiz%NetBSD.org@localhost>]

Hi!

When building firefox in my bulk builds, I sometimes see
non-reproducible errors like this one:

   0:          0x19147a8 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hc7af7c8c491f235f
   1:          0x195895c - core::fmt::write::h6704aa23384ebf6d
   2:          0x191770e - std::io::Write::write_fmt::h1ec88ed87f1a548f
   3:          0x1914536 - std::sys_common::backtrace::print::h439fad3f83fbc4b5
   4:          0x19346e3 - std::panicking::default_hook::{{closure}}::h1c39ed34efd31c8a
   5:          0x1934368 - std::panicking::default_hook::h4ee60615d1c92b96
   6:          0x193596c - std::panicking::rust_panic_with_hook::hec2f115bd3abe8a5
   7:          0x1914fb7 - std::panicking::begin_panic_handler::{{closure}}::h92a702d96e469894
   8:          0x1914c46 - std::sys_common::backtrace::__rust_end_short_backtrace::h4f5ab40c7a48f822
   9:          0x19354d2 - rust_begin_unwind
  10:           0xc71343 - core::panicking::panic_fmt::h0a6a30a68313052a
  11:          0x193d620 - std::sys::unix::thread::guard::init::h5287555ac329da10
  12:          0x190a3b9 - std::rt::init::h6e67e26812f912e8
  13:          0x190a52b - std::rt::lang_start_internal::h927544304a5690c7
  14:           0xcf2cd5 - main
  15:           0xbf637d - ___start
                               at /usr/src/lib/csu/common/crt0-common.c:350:2
fatal runtime error: initialization or cleanup bug


It does not happen every time, but regularly.

Is this a bug in rust?
 Thomas