Add cargo fmt script

Fix platform

 - Add a rustfmt config
 - Get the current code passing the formatter

Dan Robertson authored 7 years ago and Dan Robertson committed 7 years ago

 - Add cfg to extern crate sc. It is not used by redox.
 - Fix bad syntax in brk implementation for redox
 - nits
   - style: update brk implementation for linux
   - style: no space between not operator and ptr.is_null
   - style: should be a space around = in module path

implement some unistd

build semaphore header