ihk_os_getrusage(): Compile LWK-specific results in mcctrl

1. User asks mcctrl for the result via ihk_os_getrusage() with passing void *
2. mcctrl compiles the results and passes them to the user
3. User interprets it by using the type defined in the LWK-specific header

executer/kernel/mcctrl/mcctrl.h

@@ -490,4 +490,9 @@ struct ihk_perf_event_attr{
 	unsigned exclude_idle:1;
 };
 
+struct getrusage_desc {
+	void* rusage;
+	size_t size_rusage;
+};
+
 #endif