[INFO] updating cached repository geostran/rust-os
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/geostran/rust-os
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/geostran/rust-os" "work/ex/beta-1.38-1/sources/1.37.0/gh/geostran/rust-os"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/geostran/rust-os'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/geostran/rust-os" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/geostran/rust-os"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/geostran/rust-os'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] c4175f78926337cb03f8743a789a588229af2e3f
[INFO] sha for GitHub repo geostran/rust-os: c4175f78926337cb03f8743a789a588229af2e3f
[INFO] validating manifest of geostran/rust-os on toolchain 1.37.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of geostran/rust-os on toolchain beta-2019-08-13
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing geostran/rust-os
[INFO] finished frobbing geostran/rust-os
[INFO] frobbed toml for geostran/rust-os written to work/ex/beta-1.38-1/sources/1.37.0/gh/geostran/rust-os/Cargo.toml
[INFO] started frobbing geostran/rust-os
[INFO] finished frobbing geostran/rust-os
[INFO] frobbed toml for geostran/rust-os written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/geostran/rust-os/Cargo.toml
[INFO] crate geostran/rust-os already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing geostran/rust-os against beta-2019-08-13 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-2/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/geostran/rust-os:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+beta-2019-08-13" "build" "--frozen"`
[INFO] [stdout] ce4fc809eec8a8452fa118fd803489b6a6ed03fd9f170315fd5f6cc1afc9d479
[INFO] running `"docker" "start" "-a" "ce4fc809eec8a8452fa118fd803489b6a6ed03fd9f170315fd5f6cc1afc9d479"`
[INFO] [stderr]    Compiling rust-os v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] error: linking with `cc` failed: exit code: 1
[INFO] [stderr]   |
[INFO] [stderr]   = note: "cc" "-Wl,--as-needed" "-Wl,-z,noexecstack" "-m64" "-L" "/opt/crater/rustup-home/toolchains/beta-2019-08-13-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib" "/opt/crater/target/debug/deps/rust_os-c063eb4c9ec5e1ac.rust_os.byk3fx6n-cgu.0.rcgu.o" "-o" "/opt/crater/target/debug/deps/rust_os-c063eb4c9ec5e1ac" "-Wl,--gc-sections" "-pie" "-Wl,-zrelro" "-Wl,-znow" "-nodefaultlibs" "-L" "/opt/crater/target/debug/deps" "-L" "/opt/crater/rustup-home/toolchains/beta-2019-08-13-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-Wl,-Bstatic" "/opt/crater/rustup-home/toolchains/beta-2019-08-13-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_core-9b59dffdcd513d5d.rlib" "/opt/crater/rustup-home/toolchains/beta-2019-08-13-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcore-17392340ab2e4a97.rlib" "/opt/crater/rustup-home/toolchains/beta-2019-08-13-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcompiler_builtins-ac21508a81e3f7f3.rlib" "-Wl,-Bdynamic"
[INFO] [stderr]   = note: /opt/crater/target/debug/deps/rust_os-c063eb4c9ec5e1ac.rust_os.byk3fx6n-cgu.0.rcgu.o: In function `_start':
[INFO] [stderr]           /opt/crater/workdir/src/main.rs:13: multiple definition of `_start'
[INFO] [stderr]           /usr/lib/gcc/x86_64-linux-gnu/6/../../../x86_64-linux-gnu/Scrt1.o:(.text+0x0): first defined here
[INFO] [stderr]           /usr/lib/gcc/x86_64-linux-gnu/6/../../../x86_64-linux-gnu/Scrt1.o: In function `_start':
[INFO] [stderr]           (.text+0x12): undefined reference to `__libc_csu_fini'
[INFO] [stderr]           /usr/lib/gcc/x86_64-linux-gnu/6/../../../x86_64-linux-gnu/Scrt1.o: In function `_start':
[INFO] [stderr]           (.text+0x19): undefined reference to `__libc_csu_init'
[INFO] [stderr]           /usr/lib/gcc/x86_64-linux-gnu/6/../../../x86_64-linux-gnu/Scrt1.o: In function `_start':
[INFO] [stderr]           (.text+0x20): undefined reference to `main'
[INFO] [stderr]           /usr/lib/gcc/x86_64-linux-gnu/6/../../../x86_64-linux-gnu/Scrt1.o: In function `_start':
[INFO] [stderr]           (.text+0x26): undefined reference to `__libc_start_main'
[INFO] [stderr]           collect2: error: ld returned 1 exit status
[INFO] [stderr]           
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] error: Could not compile `rust-os`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "ce4fc809eec8a8452fa118fd803489b6a6ed03fd9f170315fd5f6cc1afc9d479"`
[INFO] running `"docker" "rm" "-f" "ce4fc809eec8a8452fa118fd803489b6a6ed03fd9f170315fd5f6cc1afc9d479"`
[INFO] [stdout] ce4fc809eec8a8452fa118fd803489b6a6ed03fd9f170315fd5f6cc1afc9d479