Use libbacktrace pretty-printing

[RalfJung]

r? @alexcrichton

[alexcrichton]

@bors: r+ rollup

always happy to help delete code :)

[bors]

📌 Commit a24565218e906097bd43db2348cdd9e078e78038 has been approved by alexcrichton

[rust-highfive]

The job x86_64-gnu-llvm-5.0 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

travis_time:end:02dd6c7c:start=1544553219482254895,finish=1544553220600916814,duration=1118661919
$ git checkout -qf FETCH_HEAD
travis_fold:end:git.checkout

Encrypted environment variables have been removed for security reasons.
See https://docs.travis-ci.com/user/pull-requests/#Pull-Requests-and-Security-Restrictions
$ export SCCACHE_BUCKET=rust-lang-ci-sccache2
$ export SCCACHE_REGION=us-west-1
Setting environment variables from .travis.yml
$ export IMAGE=x86_64-gnu-llvm-5.0
---
[00:46:16]    Compiling failure v0.1.3
[00:46:16] error[E0034]: multiple applicable items in scope
[00:46:16]    --> /cargo/registry/src/github.heygears.com-1ecc6299db9ec823/failure-0.1.3/src/backtrace/mod.rs:132:20
[00:46:16]     |
[00:46:16] 132 |                 bt.fmt(f)
[00:46:16]     |                    ^^^ multiple `fmt` found
[00:46:16]     |
[00:46:16]     = note: candidate #1 is defined in an impl of the trait `std::fmt::Debug` for the type `backtrace::backtrace::Backtrace`
[00:46:16]     = note: candidate #2 is defined in an impl of the trait `std::fmt::Display` for the type `backtrace::backtrace::Backtrace`
[00:46:16] error[E0034]: multiple applicable items in scope
[00:46:16]    --> /cargo/registry/src/github.heygears.com-1ecc6299db9ec823/failure-0.1.3/src/backtrace/mod.rs:140:20
[00:46:16]     |
[00:46:16]     |
[00:46:16] 140 |                 bt.fmt(f)
[00:46:16]     |                    ^^^ multiple `fmt` found
[00:46:16]     error: build failed
[00:46:16] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "build" "--target" "x86_64-unknown-linux-gnu" "-j" "4" "--release" "--locked" "--color" "always" "--manifest-path" "/checkout/src/tools/compiletest/Cargo.toml" "--message-format" "json"
[00:46:16] expected success, got: exit code: 101
[00:46:16] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test
[00:46:16] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test
[00:46:16] Build completed unsuccessfully in 0:00:51
[00:46:16] make: *** [check] Error 1
[00:46:16] Makefile:58: recipe for target 'check' failed
122892 ./obj/build/x86_64-unknown-linux-gnu/stage0-bootstrap-tools/x86_64-unknown-linux-gnu/release
115664 ./obj/build/x86_64-unknown-linux-gnu/stage0-bootstrap-tools/x86_64-unknown-linux-gnu/release/deps
115340 ./src/llvm/test/CodeGen
107892 ./obj/build/x86_64-unknown-linux-gnu/stage0/lib/rustlib/x86_64-unknown-linux-gnu/codegen-backends
---
travis_time:end:2208208e:start=1544556006901013071,finish=1544556006907334300,duration=6321229
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:191e172a
$ ln -s . checkout && for CORE in obj/cores/core.*; do EXE=$(echo $CORE | sed 's|obj/cores/

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[RalfJung]

@bors r-

[00:46:16] error[E0034]: multiple applicable items in scope
[00:46:16]    --> /cargo/registry/src/github.heygears.com-1ecc6299db9ec823/failure-0.1.3/src/backtrace/mod.rs:132:20
[00:46:16]     |
[00:46:16] 132 |                 bt.fmt(f)
[00:46:16]     |                    ^^^ multiple `fmt` found

This conflicts with failure 0.1.3, unfortunately.

[RalfJung]

With backtrace 0.3.11, the compat-problems should be gone.

@bors r=alexcrichton rollup

[bors]

📌 Commit 8e994a2 has been approved by alexcrichton