time: yield accurate_sleep instead of relaxing the cpu

core/time/time_unix.odin

@@ -1,6 +1,8 @@
 //+build linux, darwin, freebsd, openbsd
 package time
 
+import "core:sys/unix"
+
 IS_SUPPORTED :: true // NOTE: Times on Darwin are UTC.
 
 when ODIN_OS == .Darwin {
@@ -17,6 +19,10 @@ foreign libc {
 	@(link_name="nanosleep")     _unix_nanosleep     :: proc(requested: ^TimeSpec, remaining: ^TimeSpec) -> i32 ---
 }
 
+_yield :: proc "contextless" () {
+	unix.sched_yield()
+}
+
 TimeSpec :: struct {
 	tv_sec  : i64,  /* seconds */
 	tv_nsec : i64,  /* nanoseconds */