Need help with emscripten port

I’m afraid I accomplished little on emscripten yesterday. Let’s think more concretely about how to divide up the work. I’ve updated the wasm issue on the tracker with the tasks.

@jer is there anything particular you want to tackle? I’m thinking a good task for @rschulman would be to get make check working successfully, just add ignore-emscripten tags. @rschulman are you interested in doing that?

Run a single set of tests with a command like

python src/bootstrap/bootstrap.py --step check-rpass --target=asmjs-unknown-emscripten

The full set of test ‘steps’ is:

check-rpass check-rpass-full check-rpass-valgrind check-cfail check-cfail-full check-pfail check-rfail check-rfail-full check-pretty check-pretty-rpass check-pretty-rpass-full check-pretty-rfail check-pretty-rfail-full check-pretty-rpass-valgrind check-mir-opt check-codegen check-codegen-units check-incremental check-ui check-debug-info check-rustdoc check-docs check-rmake check-crate-rustc check-cargotest

Each of these can be run individually while sussing out the errors, then make check will do the full check. I’m not sure how some of these interact with the emscripten target.