build command crashes when "panic" codegen option is set to "abort"

[hhirtz]

cargo version: cargo 1.54.0-nightly (e931e4796 2021-05-24) and cargo 1.52.0 (69767412a 2021-04-21)

html5ever version: 57eb334

 $ RUSTFLAGS="-C panic=abort" cargo build
error: failed to run custom build command for `markup5ever v0.10.1 (/home/hubert/programmes/html5ever/markup5ever)`

Caused by:
  process didn't exit successfully: `/home/hubert/programmes/html5ever/target/debug/build/markup5ever-209a2feed7c451e1/build-script-build` (signal: 6, SIGABRT: process abort signal)
warning: build failed, waiting for other jobs to finish...
error: build failed

Otherwise, when using RUSTFLAGS="-C panic=unwind" (the default option for this codegen option) the build succeeds on both stable and nightly.

See https://doc.rust-lang.org/rustc/codegen-options/index.html#panic

[hhirtz]

Sorry for the noise, the crash is due to proc-macro2...

dtolnay/proc-macro2#218