add API: timing

src/rvprof_internal.h

@@ -151,6 +151,14 @@ void symbol_array_cleanup(symbol_array_t* arr);
 int rvprof_memory_add_stack_id_to_function(int func_id, int stack_id);
 int rvprof_memory_add_caller_to_function(int func_id, const char* caller);
 
+//timing
+rvprof_error_t rvprof_timing_init(void);
+uint64_t rvprof_timing_get_current(void);
+uint64_t rvprof_timing_get_cycles(void);
+double rvprof_timing_to_seconds(uint64_t nanoseconds);
+int rvprof_timing_test_cycle_counter(void);
+
+
 
 #ifdef __cplusplus
 }