build-brson-emscripten.md

Build Rust with Emscripten support

1. curl -O https://s3.amazonaws.com/mozilla-games/emscripten/releases/emsdk-portable.tar.gz
2. tar -xzf emsdk-portable.tar.gz
3. source emsdk_portable/emsdk_env.sh
4. emsdk update
5. emsdk install sdk-incoming-64bit
6. emsdk activate sdk-incoming-64bit
7. cd ~/src
8. git clone https://github.com/brson/rust --branch emscripten-new && cd rust
9. cd src/llvm && git remote add brson https://github.com/brson/llvm && git fetch brson && cd ../..
10. ./configure --enable-rustbuild --target=asmjs-unknown-emscripten
11. python2 src/bootstrap/bootstrap.py -v --step libtest --stage 2 --target asmjs-unknown-emscripten
12. python2 src/bootstrap/bootstrap.py --step check-rpass --target=asmjs-unknown-emscripten

If anyone sees the following error during step (3):

Traceback (most recent call last):
  File "./emsdk", line 1797, in <module>
    sys.exit(main())
  File "./emsdk", line 1496, in main
    load_sdk_manifest()
  File "./emsdk", line 1291, in load_sdk_manifest
    for p, v in vars(t2).iteritems():
AttributeError: 'dict' object has no attribute 'iteritems'
-bash: ./emsdk_set_env.sh: No such file or directory

This means you need to be using python2, not python3