Auto merge of #2350 - rtzoeller:solarish_scheduler, r=JohnTitor

Add sched_get/setparam and sched_get/setscheduler to Solarish

Also define scheduling constants for illumos.

src/unix/solarish/mod.rs

@@ -2105,6 +2105,14 @@ pub const PRIO_PROCESS: ::c_int = 0;
 pub const PRIO_PGRP: ::c_int = 1;
 pub const PRIO_USER: ::c_int = 2;
 
+pub const SCHED_OTHER: ::c_int = 0;
+pub const SCHED_FIFO: ::c_int = 1;
+pub const SCHED_RR: ::c_int = 2;
+pub const SCHED_SYS: ::c_int = 3;
+pub const SCHED_IA: ::c_int = 4;
+pub const SCHED_FSS: ::c_int = 5;
+pub const SCHED_FX: ::c_int = 6;
+
 // As per sys/socket.h, header alignment must be 8 bytes on SPARC
 // and 4 bytes everywhere else:
 #[cfg(target_arch = "sparc64")]
@@ -2512,6 +2520,14 @@ extern "C" {
     pub fn pthread_kill(thread: ::pthread_t, sig: ::c_int) -> ::c_int;
     pub fn sched_get_priority_min(policy: ::c_int) -> ::c_int;
     pub fn sched_get_priority_max(policy: ::c_int) -> ::c_int;
+    pub fn sched_getparam(pid: ::pid_t, param: *mut sched_param) -> ::c_int;
+    pub fn sched_setparam(pid: ::pid_t, param: *const sched_param) -> ::c_int;
+    pub fn sched_getscheduler(pid: ::pid_t) -> ::c_int;
+    pub fn sched_setscheduler(
+        pid: ::pid_t,
+        policy: ::c_int,
+        param: *const ::sched_param,
+    ) -> ::c_int;
     pub fn sem_unlink(name: *const ::c_char) -> ::c_int;
     pub fn daemon(nochdir: ::c_int, noclose: ::c_int) -> ::c_int;
     #[cfg_attr(