Add time.read_cycle_counter

core/time/time.odin

@@ -124,6 +124,14 @@ clock :: proc(t: Time) -> (hour, min, sec: int) {
 }
 
 
+read_cycle_counter :: proc() -> u64 {
+	foreign _ {
+		@(link_name="llvm.readcyclecounter")
+		llvm_readcyclecounter :: proc "none" () -> u64 ---
+	}
+	return llvm_readcyclecounter();
+}
+