WASM build broken on newest nightly for MacOS

[janhohenheim]

running cargo build --target wasm32-unknown-unknown on rustc 1.30.0-nightly (a8c11d216 2018-09-06) returns the following:

error: linking with `rust-lld` failed: signal: 6
note: dyld: Library not loaded: @rpath/libLLVM.dylib
            Referenced from: /Users/jnf/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/bin/rust-lld
            Reason: image not found

Might be related to #53813

[matthiaskrgr]

I think this might be fixed in the next nightly: #54018

[janhohenheim]

Yeah, that looks pretty relevant. Thanks a bunch!

[rbalicki2]

I can confirm this is fixed on rustc 1.30.0-nightly (fc81e3624 2018-09-07)