Maybe allow ipc-channel to build using rust stable on windows

[staktrace]

Right now if I try to build ipc-channel using stable rust (1.12.1 d4f39402a 2016-10-19) on windows, it fails with this error:

error[E0554]: #[feature] may not be used on the stable release channel
  --> C:\Users\kats\zspace\mozilla-git\third_party\rust\ipc-channel\src\lib.rs:11:4
   |
11 |                   feature(mpsc_select))]
   |                   ^^^^^^^^^^^^^^^^^^^^^

I'm not entirely sure what mpsc_select is, because that token doesn't appear anywhere else in the repo. Can this be removed, or can be rewritten using stuff that compiles with stable rust?

/cc @Ms2ger (who originally added the line in f4fef7d)
/cc @jrmuizel as FYI

[emilio]

That's mainly #108, I guess.

[antrik]

After pondering this for a while, I tend to agree with @emilio : for practical purposes, the solution to this issue is probably in making sure all platforms get a "real" inter-process implementation. The inprocess back-end is really just a partial work-around; and we can't count on mpsc_select() getting stabilised in the foreseeable future (see rust-lang/rust#27800 ) -- nor is there enough incentive for a major rewrite to avoid this dependency...

[Xaeroxe]

This now compiles on Rust stable for Windows. It should probably be closed.

[staktrace]

Thanks! Closing. (I didn't verify myself, and don't need this anymore myself either)