Add completely untested redox epoll implementation

See merge request redox-os/relibc!211

Implement rand_r(), strnlen_s(), tempnam(), tmpnam()

See merge request redox-os/relibc!210

Handle zero len for strerror_r

See merge request redox-os/relibc!209

Resolve "BufferedVaList::index may read out of bounds"

Closes #140

See merge request redox-os/relibc!208

Set errno in alloc functions and add further tests

See merge request redox-os/relibc!205

Just a small step along the way to reduce the massive wall of spam
every time you compile.

This was done partly automagically with `cargo fix`. The rest was me
deleting or commenting out a bunch of variables. Hope nothing was
important...

https://github.com/BurntSushi/rust-memchr is supposed to be a whole
lot faster :)