Try Travis downgrade for emscripten
Try Travis downgrade for emscripten

… this works around failure in the emscripten targets. Unfortunately
that failure (japaric/cross#110) makes No Sense™—it apparently depends
on the Travis environment, but emscripten is in the docker image that
comes with cross and rust comes from rustup …

rust-locale/locale_config,rust-locale/locale_config