Add scanf

See merge request redox-os/relibc!134

sys_wait: implement C macros properly

See merge request redox-os/relibc!133

Remove the broken Rust functions and instead provide C macros in a
`include/bits` header. The C macros were taken from musl.

Fix compilation error in `sys_wait`

See merge request redox-os/relibc!132

Add `sys_wait` functions (Fixes #81)

Closes #81

See merge request redox-os/relibc!131

Update `platform::rawfile`

Make functions taking raw pointer return &'a instead of &'static

Simplify cstr_from_bytes_with_nul_unchecked()

The original implementation is modified from the `Cstr` method, but the
complexity there exists because it is trying to convert to the DST `Cstr`.

This is technically more correct, and matches the pointer methods in the
standard library.

Update ralloc. Closes GH-83.

Add optimized version of memchr

Implement clock() and add CLOCK_* constants

stdlib: implement qsort() as an introsort

Fix a bug in printf()