Add schedule params & priority pthread functions
Add schedule params & priority pthread functions

mneumann/libc,cactorium/libc,rust-lang-nursery/libc,rust-lang/libc,rust-lang-nursery/libc,cactorium/libc,mneumann/libc,cactorium/libc,rust-lang/libc,rust-lang/libc,mneumann/libc,rust-lang-nursery/libc