[INFO] updating cached repository Gen-OS/bbb-proof-of-concept
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/Gen-OS/bbb-proof-of-concept
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/Gen-OS/bbb-proof-of-concept" "work/ex/beta-1.38-1/sources/1.37.0/gh/Gen-OS/bbb-proof-of-concept"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/Gen-OS/bbb-proof-of-concept'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/Gen-OS/bbb-proof-of-concept" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Gen-OS/bbb-proof-of-concept"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Gen-OS/bbb-proof-of-concept'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 6721a71feb162541895451ac00155c8c23605361
[INFO] sha for GitHub repo Gen-OS/bbb-proof-of-concept: 6721a71feb162541895451ac00155c8c23605361
[INFO] validating manifest of Gen-OS/bbb-proof-of-concept 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 Gen-OS/bbb-proof-of-concept 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 Gen-OS/bbb-proof-of-concept
[INFO] finished frobbing Gen-OS/bbb-proof-of-concept
[INFO] frobbed toml for Gen-OS/bbb-proof-of-concept written to work/ex/beta-1.38-1/sources/1.37.0/gh/Gen-OS/bbb-proof-of-concept/Cargo.toml
[INFO] started frobbing Gen-OS/bbb-proof-of-concept
[INFO] finished frobbing Gen-OS/bbb-proof-of-concept
[INFO] frobbed toml for Gen-OS/bbb-proof-of-concept written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Gen-OS/bbb-proof-of-concept/Cargo.toml
[INFO] crate Gen-OS/bbb-proof-of-concept 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] [stderr] error: failed to run `rustc` to learn about target-specific information
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustc - --crate-name ___ --print=file-names --target thumbv7a-none-eabi --crate-type bin --crate-type rlib --crate-type dylib --crate-type cdylib --crate-type staticlib --crate-type proc-macro` (exit code: 1)
[INFO] [stderr] --- stderr
[INFO] [stderr] error: Error loading target specification: Field target-c-int-width in target specification is required
[INFO] [stderr]   |
[INFO] [stderr]   = help: Use `--print target-list` for a list of built-in targets
[INFO] [stderr] 
[INFO] [stderr] 
[ERROR] this task or one of its parent failed!
[ERROR] command `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"` failed