--- ray/src/gen/sun.c	1989/09/10 16:45:19	1.2
+++ ray/src/gen/sun.c	2009/06/06 20:18:32	2.5
@@ -1,9 +1,6 @@
-/* Copyright (c) 1989 Regents of the University of California */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char	RCSid[] = "$Id: sun.c,v 2.5 2009/06/06 20:18:32 greg Exp $";
 #endif
-
 /*
  *           SOLAR CALCULATIONS
  *
@@ -11,16 +8,24 @@ static char SCCSid[] = "$SunId$ LBL";
  *
  */
 
-#define  PI  3.141592654
+#include  <math.h>
 
+#ifdef M_PI
+#define  PI	M_PI
+#else
+#define  PI	3.141592653589793
+#endif
+
 double  s_latitude = 0.66;	/* site latitude (radians) */
 double  s_longitude = 2.13;	/* site longitude (radians) */
 double  s_meridian = 2.0944;	/* standard meridian (radians) */
 
 
 int
-jdate(month, day)		/* Julian date (days into year) */
-int  month, day;
+jdate(		/* Julian date (days into year) */
+	int month,
+	int day
+)
 {
 	static short  mo_da[12] = {0,31,59,90,120,151,181,212,243,273,304,334};
 	
@@ -29,11 +34,10 @@ int  month, day;
 
 
 double
-stadj(jd)		/* solar time adjustment from Julian date */
-int  jd;
+stadj(		/* solar time adjustment from Julian date */
+	int  jd
+)
 {
-	double  sin();
-
 	return( 0.170 * sin( (4*PI/373) * (jd - 80) ) -
 		0.129 * sin( (2*PI/355) * (jd - 8) ) +
 		12 * (s_meridian - s_longitude) / PI );
@@ -41,32 +45,31 @@ int  jd;
 
 
 double
-sdec(jd)		/* solar declination angle from Julian date */
-int  jd;
+sdec(		/* solar declination angle from Julian date */
+	int  jd
+)
 {
-	double  sin();
-
 	return( 0.4093 * sin( (2*PI/368) * (jd - 81) ) );
 }
 
 
 double
-salt(sd, st)	/* solar altitude from solar declination and solar time */
-double  sd, st;
+salt(	/* solar altitude from solar declination and solar time */
+	double sd,
+	double st
+)
 {
-	double  sin(), cos(), asin();
-
 	return( asin( sin(s_latitude) * sin(sd) -
 			cos(s_latitude) * cos(sd) * cos(st*(PI/12)) ) );
 }
 
 
 double
-sazi(sd, st)	/* solar azimuth from solar declination and solar time */
-double  sd, st;
+sazi(	/* solar azimuth from solar declination and solar time */
+	double sd,
+	double st
+)
 {
-	double  sin(), cos(), atan2();
-
 	return( -atan2( cos(sd)*sin(st*(PI/12)),
  			-cos(s_latitude)*sin(sd) -
  			sin(s_latitude)*cos(sd)*cos(st*(PI/12)) ) );