LibC: Flatten malloc() and free()

This allows UE to ignore the full range of these functions instead of
just the malloc() and free() bodies.

Libraries/LibC/malloc.cpp

@@ -385,7 +385,7 @@ static void free_impl(void* ptr)
     }
 }
 
-void* malloc(size_t size)
+[[gnu::flatten]] void* malloc(size_t size)
 {
     void* ptr = malloc_impl(size);
     if (s_profiling)
@@ -393,7 +393,7 @@ void* malloc(size_t size)
     return ptr;
 }
 
-void free(void* ptr)
+[[gnu::flatten]] void free(void* ptr)
 {
     if (s_profiling)
         perf_event(PERF_EVENT_FREE, reinterpret_cast<FlatPtr>(ptr), 0);