silence top(1) warnings

[Paul Irofti]

Okay?

Index: top.c
===================================================================
RCS file: /cvs/src/usr.bin/top/top.c,v
retrieving revision 1.76
diff -u -p -r1.76 top.c
--- top.c       16 Dec 2011 14:50:24 -0000      1.76
+++ top.c       20 Apr 2012 15:29:05 -0000
@@ -264,8 +264,9 @@ int
 main(int argc, char *argv[])
 {
        char *uname_field = "USERNAME", *header_text, *env_top;
-       char *(*get_userid)(uid_t) = username, **preset_argv, **av;
-       int preset_argc = 0, ac, active_procs, i;
+       char *(*get_userid)(uid_t) = username;
+       char **preset_argv = NULL, **av = argv;
+       int preset_argc = 0, ac = argc, active_procs, i;
        sigset_t mask, oldmask;
        time_t curr_time;
        caddr_t processes;