Missing rust_eh_personality with wasm32-unknown-emscripten

[CryZe]

When compiling with the wasm32-unknown-emscripten target, the recent nightly compilers can't seem to find the rust_eh_personality symbol. https://travis-ci.org/LiveSplit/livesplit-core/jobs/444812213#L605
It works just fine with the asmjs-unknown-emscripten target.

[nstoddard]

I've seen this too, but only when panic = 'abort' is enabled. Is that enabled for your project?

[CryZe]

Yeah I have it set to abort.