Export uv functions from rustrt, remove wrappers

[brson]

There is some linkage issue causing the uv API to not be exported from rustrt, and as a result we've accumulated a bunch of functions prefixed with rust_uv that do nothing but wrap them. Figure out how to make the uv API public and delete all these functions.

[jjjjw]

So is uv going to be in core then? #4956

[brson]

The long-term plan is for uv to be in its own crate and imported as the default I/O implementation, not in core.

[luqmana]

Adding uv_* to rt/rustrt.def.in should reexport all the libuv symbols.

[brson]

Adding uv_* did not work on windows: http://buildbot.rust-lang.org/builders/auto-win/builds/1050

[brson]

uv_.* parses but linking on windows results in undefined references.

[msullivan]

Do we have any idea what the root cause is here?

[brson]

I don't know why this is on a milestone. Removing.

[alexcrichton]

I did this awhile back, libuv is statically linked, exporting all those functions, and I removed all wrappers that weren't just there to access fields of structs we don't know the layout of in rust.