diff -urN memtester-4.3.0/tests.c memtester-4.3.0-bak/tests.c
--- memtester-4.3.0/tests.c	2012-06-10 05:45:22.000000000 +0800
+++ memtester-4.3.0-bak/tests.c	2021-08-04 17:09:27.971110499 +0800
@@ -27,6 +27,9 @@
 #define PROGRESSOFTEN 2500
 #define ONE 0x00000001L

+type_mword8 mword8;
+type_mword16 mword16;
+
 /* Function definitions. */

 int compare_regions(ulv *bufa, ulv *bufb, size_t count) {
diff -urN memtester-4.3.0/types.h memtester-4.3.0-bak/types.h
--- memtester-4.3.0/types.h	2012-06-10 05:45:22.000000000 +0800
+++ memtester-4.3.0-bak/types.h	2021-08-04 17:09:10.390965532 +0800
@@ -25,12 +25,15 @@
     int (*fp)();
 };

-union {
+typedef union {
     unsigned char bytes[UL_LEN/8];
     ul val;
-} mword8;
+} type_mword8;

-union {
+typedef union {
     unsigned short u16s[UL_LEN/16];
     ul val;
-} mword16;
+} type_mword16;
+
+extern type_mword8 mword8;
+extern type_mword16 mword16;