Disable i128 and u128 on emscripten (fixes #669)

[svenstaro]

This was also reported as #669, koute/cargo-web#152 and emscripten-core/emscripten-fastcomp#169.

Basically emscripten can't properly deal with i128 and u128. This should be fixed in emscripten upstream but it's unlikely to happen. This is the best we can do. This also changes the .travis-ci.yml so that this problem doesn't re-occur without getting caught.

[svenstaro]

The failure seems unrelated to my changes.

[svenstaro]

You can get this building by clearing the cache.

[dhardy]

I tried clearing the cache (twice now I think). No luck there.

[svenstaro]

I fixed it @dhardy

[svenstaro]

Could you make a release with this included?

[dhardy]

@svenstaro why are my builds now all failing with this?

$ EMCC_CFLAGS="-s ERROR_ON_UNDEFINED_SYMBOLS=0" cargo web test --target wasm32-unknown-emscripten --no-run
Downloading emscripten-1.38.19-1-x86_64-unknown-linux-gnu.tgz...
2.73 MB / 201.71 MB [>----------------------------

[svenstaro]

@dhardy taking a look.

[svenstaro]

That's really weird though, isn't it? Pull requests work, your master branch builds do not.

[svenstaro]

The only thing that's different at this step between PRs and master is secrets, env vars, and the cache key as far as I know. I can't see your secrets and env vars but can you check those and see whether there's anything weird? Also, could you try clearing cache?