diff --git a/tools/hitag2crack/crack5opencl/ht2crack5opencl.c b/tools/hitag2crack/crack5opencl/ht2crack5opencl.c
index 924932b2c..ec261dff8 100644
--- a/tools/hitag2crack/crack5opencl/ht2crack5opencl.c
+++ b/tools/hitag2crack/crack5opencl/ht2crack5opencl.c
@@ -35,6 +35,18 @@
 #include "hitag2.h"
 #include "dolphin_macro.h"
 
+#if defined(__MINGW64__)
+#define	timersub(a, b, result) \
+  do { \
+    (result)->tv_sec = (a)->tv_sec - (b)->tv_sec; \
+    (result)->tv_usec = (a)->tv_usec - (b)->tv_usec; \
+    if ((result)->tv_usec < 0) { \
+      --(result)->tv_sec; \
+      (result)->tv_usec += 1000000;\
+    } \
+  } while (0)
+#endif
+
 #define MAX_BITSLICES 32
 #define VECTOR_SIZE (MAX_BITSLICES/8)