diff --git a/common/rng_sfmt.cpp b/common/rng_sfmt.cpp
index 2e93e44b..ad803b7d 100644
--- a/common/rng_sfmt.cpp
+++ b/common/rng_sfmt.cpp
@@ -5,7 +5,9 @@
 
 // This is from gcc sources, namely from fixincludes/inclhack.def
 // On C++11 systems, <cstdint> could be included instead.
+#ifndef UINT64_MAX
 #define UINT64_MAX (~(uint64_t)0)
+#endif
 
 RNG_SFMT::RNG_SFMT(QObject *parent)
 	: RNG_Abstract(parent)