8c604dc940
Here's another go at adding emscripten support. This needs to wait again on new [libc definitions](https://github.com/rust-lang-nursery/libc/pull/122) landing. To get the libc definitions right I had to add support for i686-unknown-linux-musl, which are very similar to emscripten's, which are derived from arm/musl. This branch additionally removes the makefile dependency on the `EMSCRIPTEN` environment variable by not building the unused compiler-rt. Again, this is not sufficient for actually compiling to asmjs since it needs additional LLVM patches. r? @alexcrichton
See the README.md in ../librustc.