--- epplets/CalcEphem.h
+++ epplets/CalcEphem.h
@@ -1,5 +1,6 @@
 #include <stdio.h>
 #include <math.h>
+#include <string.h>
 
 #define DegPerRad       57.29577951308232087680
 #define RadPerDeg        0.01745329251994329576