bt

cfg: version 1.12.0-dev (8eb7e6a0f 2016-07-28)
cfg: build triple x86_64-apple-darwin
cfg: host triples x86_64-apple-darwin
cfg: target triples x86_64-apple-darwin
cfg: enabling debug assertions (CFG_ENABLE_DEBUG_ASSERTIONS)
cfg: enabling debuginfo (CFG_ENABLE_DEBUGINFO)
cfg: host for x86_64-apple-darwin is x86_64
cfg: os for x86_64-apple-darwin is apple-darwin
cfg: have good valgrind for x86_64-apple-darwin
cfg: using CC=ccache clang (CFG_CC)
cfg: using CXX=clang++ (CFG_CXX)
cfg: disabling valgrind run-pass tests
rustc: x86_64-apple-darwin/stage1/lib/rustlib/x86_64-apple-darwin/lib/libstd
src/liblibc/src/unix/bsd/apple/mod.rs:959:58: 962:2 error: constant contains unimplemented expression type [E0019]
src/liblibc/src/unix/bsd/apple/mod.rs:959
                                                                                                   ^
error: internal compiler error: unexpected panic
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'encountered error with `-Z treat_err_as_bug', src/librustc_errors/lib.rs:544
stack backtrace:
   1:        0x1066f4d75 - std::sys::backtrace::tracing::imp::write::hf504bc08f2a3011f
   2:        0x10670378a - std::panicking::default_hook::_{{closure}}::h49b28af2d05b6140
   3:        0x1067032d1 - std::panicking::default_hook::hf5d79ad4f1ead81e
   4:        0x1066c1ba2 - std::panicking::rust_panic_with_hook::h9a3925e37821d434
   5:        0x1064e2064 - std::panicking::begin_panic::hf0f914ab539f4b11
   6:        0x1064e2e3d - rustc_errors::DiagnosticBuilder::emit::haacc27515381e284
   7:        0x1064e8cee - rustc_errors::Handler::emit_with_code::hc1ffd0a5cfd44f7f
   8:        0x1027cfbca - rustc_errors::Handler::span_err_with_code::ha1627958f31e7823
   9:        0x1027cfb06 - rustc::session::Session::span_err_with_code::hd4750c3263581877
  10:        0x1027cf9be - rustc_mir::transform::qualify_consts::Qualifier::not_const::hf00c5c9be36b1d20
  11:        0x1027d0cb1 - _<rustc_mir..transform..qualify_consts..Qualifier<'a, 'tcx, 'tcx> as rustc..mir..visit..Visitor<'tcx>>::visit_lvalue::hbd95355697747f12
  12:        0x1027d0989 - rustc_mir::transform::qualify_consts::Qualifier::assign::h4239084ce71acb76
  13:        0x1027d4b0c - _<rustc_mir..transform..qualify_consts..Qualifier<'a, 'tcx, 'tcx> as rustc..mir..visit..Visitor<'tcx>>::visit_statement::h7a506e186907eb33
  14:        0x1027d1180 - rustc_mir::transform::qualify_consts::Qualifier::qualify_const::h7fc460a51d2d1d88
  15:        0x1027d25f2 - rustc_mir::transform::qualify_consts::qualify_const_item_cached::h40fe74cb097278e4
  16:        0x1027d1b0f - _<rustc_mir..transform..qualify_consts..Qualifier<'a, 'tcx, 'tcx> as rustc..mir..visit..Visitor<'tcx>>::visit_operand::ha9fe57a69e4a6ab8
  17:        0x1027d45de - _<rustc_mir..transform..qualify_consts..Qualifier<'a, 'tcx, 'tcx> as rustc..mir..visit..Visitor<'tcx>>::visit_terminator_kind::_{{closure}}::hc8a6d24bb9038595
  18:        0x1027d3c6e - _<rustc_mir..transform..qualify_consts..Qualifier<'a, 'tcx, 'tcx> as rustc..mir..visit..Visitor<'tcx>>::visit_terminator_kind::h895b6b7d0f75111f
  19:        0x1027d1202 - rustc_mir::transform::qualify_consts::Qualifier::qualify_const::h7fc460a51d2d1d88
  20:        0x1027d6723 - _<rustc_mir..transform..qualify_consts..QualifyAndPromoteConstants as rustc..mir..transform..MirMapPass<'tcx>>::run_pass::ha25c7d0c349858c3
  21:        0x102e6036a - rustc::mir::transform::Passes::run_passes::hb33773e3bc2328f9
  22:        0x1014f983f - rustc_driver::driver::phase_3_run_analysis_passes::_{{closure}}::_{{closure}}::h9877a4b3099a0483
  23:        0x1014f0970 - rustc_driver::driver::phase_3_run_analysis_passes::_{{closure}}::he1de538a7584312e
  24:        0x1014ebb69 - rustc::ty::context::TyCtxt::create_and_enter::he5466411552b055e
  25:        0x10147ed52 - rustc_driver::driver::compile_input::h2d1b58b831f06a86
  26:        0x101468983 - rustc_driver::run_compiler::h833483649bdaa9c3
  27:        0x10146589c - std::panicking::try::call::hd16aacc09eeeaf9e
  28:        0x10670a58b - __rust_try
  29:        0x10670a525 - __rust_maybe_catch_panic
  30:        0x101466425 - _<F as alloc..boxed..FnBox<A>>::call_box::hbf614b3f826456b6
  31:        0x1067020d8 - std::sys::thread::Thread::new::thread_start::h2e98425c7fffa990
  32:     0x7fff8d48d99c - _pthread_body
  33:     0x7fff8d48d919 - _pthread_start

make: *** [x86_64-apple-darwin/stage1/lib/rustlib/x86_64-apple-darwin/lib/stamp.std] Error 101