Auto merge of rust-lang#611 - vityafx:add-pthread-priority-functions, r=alexcrichton

Add schedule params & priority pthread functions

Fixes rust-lang#609. Provides bindings to `pthread_getschedparam`, `pthread_setschedparam` and `pthread_setschedprio` functions.

P.S. My first PR in such a project.
P.P.S. `libc-test` crashed at building stage with a lot of errors, so I hope `travis` will do a check.
P.P.P.S. These functions are tested to work on Linux (Ubuntu 14.04) with my own crate. I will release it next week, it provides ability to control thread schedule policies and priorities.

Author: bors

src/unix/notbsd/linux/mod.rs

@@ -927,6 +927,8 @@ extern {
                        serv: *mut ::c_char,
                        sevlen: ::socklen_t,
                        flags: ::c_int) -> ::c_int;
+    pub fn pthread_setschedprio(native: ::pthread_t,
+                                priority: ::c_int) -> ::c_int;
     pub fn prlimit(pid: ::pid_t, resource: ::c_int, new_limit: *const ::rlimit,
                    old_limit: *mut ::rlimit) -> ::c_int;
     pub fn prlimit64(pid: ::pid_t,

src/unix/notbsd/mod.rs

@@ -963,6 +963,12 @@ extern {
                                        pshared: ::c_int) -> ::c_int;
     pub fn pthread_condattr_getpshared(attr: *const pthread_condattr_t,
                                        pshared: *mut ::c_int) -> ::c_int;
+    pub fn pthread_getschedparam(native: ::pthread_t,
+                                 policy: *mut ::c_int,
+                                 param: *mut ::sched_param) -> ::c_int;
+    pub fn pthread_setschedparam(native: ::pthread_t,
+                                 policy: ::c_int,
+                                 param: *const ::sched_param) -> ::c_int;
     pub fn sched_getaffinity(pid: ::pid_t,
                              cpusetsize: ::size_t,
                              cpuset: *mut cpu_set_t) -> ::c_int;