Typo fix in memory_buffer_alloc.c
diff --git a/library/memory_buffer_alloc.c b/library/memory_buffer_alloc.c
index 2196891..33ab5ac 100644
--- a/library/memory_buffer_alloc.c
+++ b/library/memory_buffer_alloc.c
@@ -517,7 +517,7 @@
         debug_chain();
     }
 }
-#endif /* POLARSSL_MEMORY_BUFFER_ALLOC_DEBUG */
+#endif /* POLARSSL_MEMORY_DEBUG */
 
 #if defined(POLARSSL_THREADING_C)
 static void *buffer_alloc_malloc_mutexed( size_t len )