Include missing header files which define functions for which gcc has

builtins (e.g., exit).

Submitted by:	Mike Barcroft <mike@q9media.com>

usr.bin/basename/basename.c

@@ -46,6 +46,7 @@ static const char sccsid[] = "@(#)basename.c	8.4 (Berkeley) 5/4/95";
 #include <err.h>
 #include <libgen.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 

usr.bin/dirname/dirname.c

@@ -46,6 +46,7 @@ static const char sccsid[] = "@(#)dirname.c	8.4 (Berkeley) 5/4/95";
 #include <err.h>
 #include <libgen.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <unistd.h>
 
 void usage __P((void));

usr.bin/fsync/fsync.c

@@ -32,6 +32,7 @@ static const char rcsid[] =
 #include <err.h>
 #include <fcntl.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <sysexits.h>
 #include <unistd.h>
 

usr.bin/gencat/gencat.c

@@ -37,6 +37,8 @@ up-to-date.  Many thanks.
 #include <sys/stat.h>
 #include <err.h>
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 #include "gencat.h"
 

usr.bin/keyinfo/keyinfo.c

@@ -28,6 +28,7 @@
 
 #include <sys/param.h>
 #include <stdio.h>
+#include <string.h>
 #include <skey.h>
 #include <unistd.h>
 #include <err.h>

usr.bin/keylogout/keylogout.c

@@ -41,6 +41,8 @@ static const char rcsid[] =
  */
 
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 #include <rpc/key_prot.h>
 

usr.bin/leave/leave.c

@@ -49,6 +49,7 @@ static const char rcsid[] =
 #include <ctype.h>
 #include <locale.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <time.h>
 #include <unistd.h>
 

usr.bin/mkfifo/mkfifo.c

@@ -51,6 +51,7 @@ static const char rcsid[] =
 #include <err.h>
 #include <errno.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 

usr.bin/unexpand/unexpand.c

@@ -50,6 +50,7 @@ static const char rcsid[] =
  */
 #include <err.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 
 char	genbuf[BUFSIZ];