maint: use xsetmode, not xfreopen

This fixes a bug noted by Eric Blake.  Code was using xfreopen to
change files to binary mode, but this fails for stdout when in
append mode.  Such code should use xsetmode instead.  This affects
only the port on platforms like MS-Windows which distiguish text
from binary I/O.
* bootstrap.conf (gnulib_modules):
Remove xfreopen and add xsetmode.  Sort.
* src/base64.c (main):
* src/cat.c (main):
* src/cksum.c (cksum):
* src/head.c (head_file, main):
* src/md5sum.c (digest_file):
* src/od.c (open_next_file):
* src/split.c (main):
* src/sum.c (bsd_sum_file, sysv_sum_file):
* src/tac.c (tac_file, main):
* src/tail.c (tail_file):
* src/tee.c (tee_files):
* src/tr.c (main):
* src/wc.c (wc_file): Use xsetmode, not xfreopen.

src/split.c

@@ -38,8 +38,8 @@
 #include "quote.h"
 #include "safe-read.h"
 #include "sig2str.h"
-#include "xfreopen.h"
 #include "xdectoint.h"
+#include "xsetmode.h"
 #include "xstrtol.h"
 
 /* The official name of this program (e.g., no 'g' prefix).  */
@@ -1553,8 +1553,7 @@ main (int argc, char **argv)
          quoteaf (infile));
 
   /* Binary I/O is safer when byte counts are used.  */
-  if (O_BINARY && ! isatty (STDIN_FILENO))
-    xfreopen (NULL, "rb", stdin);
+  xsetmode (STDIN_FILENO, O_BINARY);
 
   /* Get the optimal block size of input device and make a buffer.  */