diff --git a/base/tools/amake/alang.h b/base/tools/amake/alang.h
index 8df3afd3..b4f97b5a 100644
--- a/base/tools/amake/alang.h
+++ b/base/tools/amake/alang.h
@@ -3,6 +3,7 @@
 
 #include <stdint.h>
 #include <stdbool.h>
+#include <stddef.h>
 
 #define OPCODES_SIZE (1024 * 1024)