Terminate execl() arguments with NULL instead of 0

Makes sure that a full 64-bits of 0 is passed in 64-bit builds, and
clears gcc warning of:

misc.c: In function ‘System’:
misc.c:114:2: warning: missing sentinel in function call

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/misc.c b/misc.c
index 0efa8e4..90e4e6c 100644
--- a/misc.c
+++ b/misc.c
@@ -111,7 +111,7 @@ System(char *s)
     int pid, status;
     if ((pid = fork ()) == 0) {
 	(void) setpgrp();
-	execl ("/bin/sh", "sh", "-c", s, 0);
+	execl ("/bin/sh", "sh", "-c", s, NULL);
     } else
 	waitpid (pid, &status, 0);
     return status;