README.md: Command line example does not work with rustc nightly 2020-04-30

[gifnksm]

The following command line option no longer works with rustc nightly due to the removal of the -Zno-landing-pads option (rust-lang/rust#70175)

export CARGO_INCREMENTAL=0
export RUSTFLAGS="-Zprofile -Ccodegen-units=1 -Copt-level=0 -Clink-dead-code -Coverflow-checks=off -Zno-landing-pads"

[wusyong]

So is it safe if we just remove no-landing-pads? Or we should also add panic=abort?

[kngwyu]

Hey guys, I also encountered this issue and removed no-landing-pads, resulting in decreased coverage(from 58% to 38%).
https://codecov.io/gh/PyO3/pyo3/branch/master/commits?from=2020-04-28%2000%3A00%3A00&to=2020-05-03%2000%3A00%3A00

Any idea?