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/date.c b/src/date.c
index 3cfcc6265..e94de6013 100644
--- a/src/date.c
+++ b/src/date.c
@@ -385,7 +385,7 @@ main (int argc, char **argv)
 	  /* POSIX says that `date -u' is equivalent to setting the TZ
 	     environment variable, so this option should do nothing other
 	     than setting TZ.  */
-	  if (putenv ("TZ=UTC0") != 0)
+	  if (putenv (bad_cast ("TZ=UTC0")) != 0)
 	    xalloc_die ();
 	  TZSET;
 	  break;