--- ray/src/px/ra_pict.c	1992/10/30 09:14:04	2.5
+++ ray/src/px/ra_pict.c	1993/06/04 14:47:37	2.6
@@ -20,6 +20,7 @@ static char SCCSid[] = "$SunId$ LBL";
  */
 
 #include <stdio.h>
+#include <math.h>
 #ifdef MSDOS
 #include <fcntl.h>
 #endif