declare program_name consistently

* src/base64.c: Likewise.
* src/basename.c: Likewise.
* src/cat.c: Likewise.
* src/chcon.c: Likewise.
* src/chgrp.c: Likewise.
* src/chmod.c: Likewise.
* src/chown.c: Likewise.
* src/chroot.c: Likewise.
* src/cksum.c: Likewise.
* src/comm.c: Likewise.
* src/cp.c: Likewise.
* src/csplit.c: Likewise.
* src/cut.c: Likewise.
* src/date.c: Likewise.
* src/dd.c: Likewise.
* src/df.c: Likewise.
* src/dircolors.c: Likewise.
* src/dirname.c: Likewise.
* src/du.c: Likewise.
* src/echo.c: Likewise.
* src/env.c: Likewise.
* src/expand.c: Likewise.
* src/expr.c: Likewise.
* src/factor.c: Likewise.
* src/fmt.c: Likewise.
* src/fold.c: Likewise.
* src/groups.c: Likewise.
* src/head.c: Likewise.
* src/hostid.c: Likewise.
* src/hostname.c: Likewise.
* src/id.c: Likewise.
* src/install.c: Likewise.
* src/join.c: Likewise.
* src/kill.c: Likewise.
* src/link.c: Likewise.
* src/ln.c: Likewise.
* src/logname.c: Likewise.
* src/ls.c: Likewise.
* src/md5sum.c: Likewise.
* src/mkdir.c: Likewise.
* src/mkfifo.c: Likewise.
* src/mknod.c: Likewise.
* src/mktemp.c: Likewise.
* src/mv.c: Likewise.
* src/nice.c: Likewise.
* src/nl.c: Likewise.
* src/nohup.c: Likewise.
* src/od.c: Likewise.
* src/paste.c: Likewise.
* src/pathchk.c: Likewise.
* src/pinky.c: Likewise.
* src/pr.c: Likewise.
* src/printenv.c: Likewise.
* src/printf.c: Likewise.
* src/ptx.c: Likewise.
* src/pwd.c: Likewise.
* src/readlink.c: Likewise.
* src/rm.c: Likewise.
* src/rmdir.c: Likewise.
* src/runcon.c: Likewise.
* src/seq.c: Likewise.
* src/setuidgid.c: Likewise.
* src/shuf.c: Likewise.
* src/sleep.c: Likewise.
* src/sort.c: Likewise.
* src/split.c: Likewise.
* src/stat.c: Likewise.
* src/stty.c: Likewise.
* src/su.c: Likewise.
* src/sum.c: Likewise.
* src/sync.c: Likewise.
* src/tac.c: Likewise.
* src/tail.c: Likewise.
* src/tee.c: Likewise.
* src/test.c: Likewise.
* src/timeout.c: Likewise.
* src/touch.c: Likewise.
* src/tr.c: Likewise.
* src/true.c: Likewise.
* src/tsort.c: Likewise.
* src/tty.c: Likewise.
* src/uname.c: Likewise.
* src/unexpand.c: Likewise.
* src/uniq.c: Likewise.
* src/unlink.c: Likewise.
* src/uptime.c: Likewise.
* src/users.c: Likewise.
* src/wc.c: Likewise.
* src/who.c: Likewise.
* src/whoami.c: Likewise.
* src/yes.c: Likewise.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/unlink.c b/src/unlink.c
index 26efb6682..0ef24480e 100644
--- a/src/unlink.c
+++ b/src/unlink.c
@@ -36,7 +36,7 @@
 #define AUTHORS proper_name ("Michael Stone")
 
 /* Name this program was run with.  */
-char *program_name;
+char const *program_name;
 
 void
 usage (int status)