--- ray/src/px/greyscale.c	1991/11/12 16:05:23	2.1
+++ ray/src/px/greyscale.c	1995/02/14 08:55:09	2.4
@@ -12,6 +12,8 @@ static char SCCSid[] = "$SunId$ LBL";
 
 #include  <stdio.h>
 
+#include  <math.h>
+
 #include  "color.h"
 
 
@@ -23,7 +25,7 @@ int  argc;
 char  *argv[];
 {
 	COLOR  col;
-	double  d1,d2,d3, atof(), log();
+	double  d1,d2,d3;
 	int  i;
 
 	printargs(argc, argv, stdout);
@@ -60,7 +62,7 @@ char  *argv[];
 greyscale(col0)			/* output our grey scale */
 COLOR  col0;
 {
-	double  exp();
+	extern double  exp();
 	COLOR  col1, col2, scanline[512];
 	double  x;
 	int  j;