--- src/GameLogic.h
+++ src/GameLogic.h
@@ -52,8 +52,8 @@
   /* Fixed interval time-based animation */
   static const int maximumFrameRate = 60;
   static const int minimumFrameRate = 15;
-  static const float updateInterval = 1.0 / maximumFrameRate;
-  static const float maxCyclesPerFrame = maximumFrameRate / minimumFrameRate;
+  static const float updateInterval;
+  static const float maxCyclesPerFrame;
 
   float lastFrameTime;
   float cyclesLeftOver;
--- src/GameLogic.cc
+++ src/GameLogic.cc
@@ -206,3 +206,6 @@
 {
   sprintf(buf, "%s/data/gfx/%s", datadir, file);
 }
+
+const float GameLogic::updateInterval = 1.0 / maximumFrameRate;
+const float GameLogic::maxCyclesPerFrame = maximumFrameRate / minimumFrameRate;