Fix a few cases that relied on 'implicit int' (constraint violation in C99).

libexec/atrun/atrun.c

@@ -83,7 +83,7 @@ static const char rcsid[] =
 
 /* File scope variables */
 
-static debug = 0;
+static int debug = 0;
 
 void perr(const char *a);
 static void usage(void);

usr.bin/gprof/gprof.c

@@ -417,7 +417,7 @@ void
 readsamples(pfile)
     FILE	*pfile;
 {
-    register i;
+    int		i;
     intmax_t	sample;
 
     if (samples == 0) {

usr.bin/nfsstat/nfsstat.c

@@ -91,6 +91,7 @@ char *sperc2(int, int);
 
 #define DELTA(field)	(nfsstats.field - lastst.field)
 
+int
 main(argc, argv)
 	int argc;
 	char **argv;

usr.sbin/mrouted/main.c

@@ -705,7 +705,7 @@ timer(i)
 static void
 cleanup()
 {
-    static in_cleanup = 0;
+    static int in_cleanup = 0;
 
     if (!in_cleanup) {
 	in_cleanup++;

usr.sbin/sliplogin/sliplogin.c

@@ -367,6 +367,7 @@ void line_flags(unit)
 }
 
 
+int
 main(argc, argv)
 	int argc;
 	char *argv[];