diff --git a/usr.bin/calendar/calendar.c b/usr.bin/calendar/calendar.c
index aae5f2a70848..5a0eefc4e97e 100644
--- a/usr.bin/calendar/calendar.c
+++ b/usr.bin/calendar/calendar.c
@@ -67,9 +67,7 @@ int f_dayBefore = 0; /* days before current date */
 int Friday = 5;	     /* day before weekend */
 
 int
-main(argc, argv)
-	int argc;
-	char *argv[];
+main(int argc, char *argv[])
 {
 	int ch;
 
@@ -143,7 +141,7 @@ main(argc, argv)
 
 
 void
-usage()
+usage(void)
 {
 	(void)fprintf(stderr, "%s\n%s\n",
 	    "usage: calendar [-a] [-A days] [-B days] [-F friday] "
diff --git a/usr.bin/calendar/calendar.h b/usr.bin/calendar/calendar.h
index fdda4b59a7cc..48fb785b20ee 100644
--- a/usr.bin/calendar/calendar.h
+++ b/usr.bin/calendar/calendar.h
@@ -41,7 +41,8 @@ extern int doall;
 extern struct iovec header[];
 extern struct tm *tp;
 extern const char *calendarFile;
-extern char *optarg;
+extern int *cumdays;
+extern struct fixs neaster, npaskha;
 
 void	 cal(void);
 void	 closecal(FILE *);
diff --git a/usr.bin/calendar/day.c b/usr.bin/calendar/day.c
index 2df00ee48aa1..90890d0c23c4 100644
--- a/usr.bin/calendar/day.c
+++ b/usr.bin/calendar/day.c
@@ -75,7 +75,8 @@ static struct fixs fnmonths[13];      /* full national months names */
 static struct fixs nmonths[13];       /* short national month names */
 
 
-void setnnames(void)
+void
+setnnames(void)
 {
 	char buf[80];
 	int i, l;
@@ -137,8 +138,7 @@ void setnnames(void)
 }
 
 void
-settime(now)
-    	time_t now;
+settime(time_t now)
 {
 	char *oldl, *lbufp;
 
@@ -170,8 +170,8 @@ settime(now)
 /* convert Day[/Month][/Year] into unix time (since 1970)
  * Day: two digits, Month: two digits, Year: digits
  */
-time_t Mktime (dp)
-    char *dp;
+time_t
+Mktime (char *dp)
 {
     time_t t;
     int d, m, y;
@@ -216,11 +216,7 @@ time_t Mktime (dp)
  * along with the matched line.
  */
 int
-isnow(endp, monthp, dayp, varp)
-	char *endp;
-	int	*monthp;
-	int	*dayp;
-	int	*varp;
+isnow(char *endp, int *monthp, int *dayp, int *varp)
 {
 	int day, flags, month = 0, v1, v2;
 
@@ -397,8 +393,7 @@ isnow(endp, monthp, dayp, varp)
 
 
 int
-getmonth(s)
-	char *s;
+getmonth(char *s)
 {
 	const char **p;
 	struct fixs *n;
@@ -417,8 +412,7 @@ getmonth(s)
 
 
 int
-getday(s)
-	char *s;
+getday(char *s)
 {
 	const char **p;
 	struct fixs *n;
@@ -441,8 +435,7 @@ getday(s)
  * ... etc ...
  */
 int
-getdayvar(s)
-	char *s;
+getdayvar(char *s)
 {
 	int offs;
 
diff --git a/usr.bin/calendar/io.c b/usr.bin/calendar/io.c
index df19e8ce3d33..ee5b9883a523 100644
--- a/usr.bin/calendar/io.c
+++ b/usr.bin/calendar/io.c
@@ -85,7 +85,7 @@ struct iovec header[] = {
 
 
 void
-cal()
+cal(void)
 {
 	int printing;
 	char *p;
@@ -166,9 +166,7 @@ cal()
 }
 
 int
-getfield(p, endp, flags)
-	char *p, **endp;
-	int *flags;
+getfield(char *p, char **endp, int *flags)
 {
 	int val, var;
 	char *start, savech;
@@ -233,7 +231,7 @@ getfield(p, endp, flags)
 char path[MAXPATHLEN];
 
 FILE *
-opencal()
+opencal(void)
 {
 	uid_t uid;
 	size_t i;
@@ -312,8 +310,7 @@ opencal()
 }
 
 void
-closecal(fp)
-	FILE *fp;
+closecal(FILE *fp)
 {
 	uid_t uid;
 	struct stat sbuf;
diff --git a/usr.bin/calendar/ostern.c b/usr.bin/calendar/ostern.c
index f000f7d5311b..833d6233f81d 100644
--- a/usr.bin/calendar/ostern.c
+++ b/usr.bin/calendar/ostern.c
@@ -43,8 +43,8 @@ __FBSDID("$FreeBSD$");
  * Astronomical Almanac".
  */
 
-int easter (year)
-    int year;            /* 0 ... abcd, NOT since 1900 */
+int
+easter(int year) /* 0 ... abcd, NOT since 1900 */
 {
     int G,	/* Golden number - 1 */
 	C,	/* Century */
@@ -73,12 +73,9 @@ int easter (year)
  */
 
 int
-geteaster(s, year)
-	char *s;
-        int year;
+geteaster(char *s, int year)
 {
 	int offset = 0;
-	extern struct fixs neaster;
 
 #define EASTER "easter"
 #define EASTERNAMELEN (sizeof(EASTER) - 1)
diff --git a/usr.bin/calendar/paskha.c b/usr.bin/calendar/paskha.c
index 3999d31c92bb..769d09152d99 100644
--- a/usr.bin/calendar/paskha.c
+++ b/usr.bin/calendar/paskha.c
@@ -43,13 +43,11 @@ static int paskha (int);
 /* (old style result) */
 
 static int
-paskha (R)
-int R;  /*year*/
+paskha(int R) /*year*/
 {
 	int a, b, c, d, e;
 	static int x = 15;
 	static int y = 6;
-	extern int *cumdays;
 
 	a = R % 19;
 	b = R % 4;
@@ -62,12 +60,9 @@ int R;  /*year*/
 /* return year day for Orthodox Easter depending days */
 
 int
-getpaskha(s, year)
-	char *s;
-        int year;
+getpaskha(char *s, int year)
 {
 	int offset;
-	extern struct fixs npaskha;
 
 	if (strncasecmp(s, PASKHA, PASKHALEN) == 0)
 	    s += PASKHALEN;