Rust 1.30 broke honggfuzz builds

[TheBlueMatt]

(at least on travis). See, eg, build at https://travis-ci.org/rust-bitcoin/rust-lightning/jobs/446288104 which fails with "note: /usr/bin/ld: __sancov_guards has both ordered [`__sancov_guards' in /home/travis/build/rust-bitcoin/rust-lightning/fuzz/hfuzz_target/x86_64-unknown-linux-gnu/release/deps/chanmon_deser_target-b3cbf469215400a7.chanmon_deser_target.7gmhrznz-cgu.1.rcgu.o] and unordered [`__sancov_guards' in /home/travis/build/rust-bitcoin/rust-lightning/fuzz/hfuzz_target/x86_64-unknown-linux-gnu/release/deps/chanmon_deser_target-b3cbf469215400a7.chanmon_deser_target.7gmhrznz-cgu.1.rcgu.o] sections"

[TheBlueMatt]

I guess this is rust-lang/rust#53945 but it doesnt appear to work on 0.5.30, which judging from git commit logs it should?

[PaulGrandperrin]

Hi @TheBlueMatt , thanks for the report. It does look like this is rust-lang/rust#53945, so the current workaround is to use RUSTFLAGS="-Clink-arg=-fuse-ld=gold" (rust-lang/rust#53945 (comment)).

As of honggfuzz-rs:0.5.30, there is a commit in the git history that tried to apply this workaround when needed (7f4cdb9) but the patch wasn't working properly so I reverted it and only applied the workaround to my test script (3644759).

TL;DR: The workaround is only present in this project test suite, but not applied to projects using it.

I'll look into fixing that this weekend, in the meantime, you can use the RUSTFLAGS environment variable if you need to.