avoid warnings about discarding "qualifiers from pointer target type"

Use the new "bad_cast" function or an actual cast-to-"(char *)"
to avoid warnings.
* src/system.h (bad_cast): Define.
* src/chown.c (main):
* src/chroot.c (main):
* src/date.c (main):
* src/du.c (main):
* src/expand.c (stdin_argv):
* src/ls.c (decode_switches):
* src/md5sum.c (main):
* src/paste.c (main):
* src/pr.c (col_sep_string, column_separator, line_separator, main):
* src/sort.c (main):
* src/split.c (main):
* src/tail.c (main):
* src/unexpand.c (stdin_argv):
* src/yes.c (main):

1 files changed, 1 insertions, 1 deletions

diff --git a/src/expand.c b/src/expand.c
index 8efb81b33..87c89152e 100644
--- a/src/expand.c
+++ b/src/expand.c
@@ -76,7 +76,7 @@ static char **file_list;
 /* Default for `file_list' if no files are given on the command line.  */
 static char *stdin_argv[] =
 {
-  "-", NULL
+  (char *) "-", NULL
 };
 
 /* True if we have ever read standard input.  */