Merge from gnulib

This incorporates:
2017-02-16 xbinary-io: rename from xsetmode
2017-02-15 xsetmode: new module
* lib-src/etags.c (main):
* lib-src/hexl.c (main):
* src/emacs.c (main) [MSDOS]:
Prefer set_binary_mode to the obsolescent SET_BINARY.
* lib/binary-io.c, lib/binary-io.h: Copy from gnulib.

lib-src/etags.c

@@ -1255,7 +1255,7 @@ main (int argc, char **argv)
       if (streq (tagfile, "-"))
 	{
 	  tagf = stdout;
-	  SET_BINARY (fileno (stdout));
+	  set_binary_mode (STDOUT_FILENO, O_BINARY);
 	}
       else
 	tagf = fopen (tagfile, append_to_tagfile ? "ab" : "wb");

lib-src/hexl.c

@@ -76,7 +76,7 @@ main (int argc, char **argv)
       else if (!strcmp (*argv, "-un") || !strcmp (*argv, "-de"))
 	{
 	  un_flag = true;
-	  SET_BINARY (fileno (stdout));
+	  set_binary_mode (fileno (stdout), O_BINARY);
 	}
       else if (!strcmp (*argv, "-hex"))
 	/* Hex is the default and is only base supported.  */;
@@ -109,7 +109,7 @@ main (int argc, char **argv)
 	{
 	  fp = stdin;
 	  if (!un_flag)
-	    SET_BINARY (fileno (stdin));
+	    set_binary_mode (fileno (stdin), O_BINARY);
 	}
       else
 	{

lib/binary-io.c

@@ -1,4 +1,37 @@
+/* Binary mode I/O.
+   Copyright 2017 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
 #include <config.h>
+
 #define BINARY_IO_INLINE _GL_EXTERN_INLINE
 #include "binary-io.h"
-typedef int dummy;
+
+#if defined __DJGPP__ || defined __EMX__
+# include <errno.h>
+# include <unistd.h>
+
+int
+__gl_setmode_check (int fd)
+{
+  if (isatty (fd))
+    {
+      errno = EINVAL;
+      return -1;
+    }
+  else
+    return 0;
+}
+#endif

lib/binary-io.h

@@ -33,15 +33,12 @@ _GL_INLINE_HEADER_BEGIN
 # define BINARY_IO_INLINE _GL_INLINE
 #endif
 
-/* set_binary_mode (fd, mode)
-   sets the binary/text I/O mode of file descriptor fd to the given mode
-   (must be O_BINARY or O_TEXT) and returns the previous mode.  */
 #if O_BINARY
 # if defined __EMX__ || defined __DJGPP__ || defined __CYGWIN__
 #  include <io.h> /* declares setmode() */
-#  define set_binary_mode setmode
+#  define __gl_setmode setmode
 # else
-#  define set_binary_mode _setmode
+#  define __gl_setmode _setmode
 #  undef fileno
 #  define fileno _fileno
 # endif
@@ -50,7 +47,7 @@ _GL_INLINE_HEADER_BEGIN
   /* Use a function rather than a macro, to avoid gcc warnings
      "warning: statement with no effect".  */
 BINARY_IO_INLINE int
-set_binary_mode (int fd, int mode)
+__gl_setmode (int fd, int mode)
 {
   (void) fd;
   (void) mode;
@@ -58,18 +55,29 @@ set_binary_mode (int fd, int mode)
 }
 #endif
 
-/* SET_BINARY (fd);
-   changes the file descriptor fd to perform binary I/O.  */
 #if defined __DJGPP__ || defined __EMX__
-# include <unistd.h> /* declares isatty() */
-  /* Avoid putting stdin/stdout in binary mode if it is connected to
-     the console, because that would make it impossible for the user
-     to interrupt the program through Ctrl-C or Ctrl-Break.  */
-# define SET_BINARY(fd) ((void) (!isatty (fd) ? (set_binary_mode (fd, O_BINARY), 0) : 0))
+extern int __gl_setmode_check (int);
 #else
-# define SET_BINARY(fd) ((void) set_binary_mode (fd, O_BINARY))
+BINARY_IO_INLINE int
+__gl_setmode_check (int fd) { return 0; }
 #endif
 
+/* Set FD's mode to MODE, which should be either O_TEXT or O_BINARY.
+   Return the old mode if successful, -1 (setting errno) on failure.
+   Ordinarily this function would be called 'setmode', since that is
+   its name on MS-Windows, but it is called 'set_binary_mode' here
+   to avoid colliding with a BSD function of another name.  */
+
+BINARY_IO_INLINE int
+set_binary_mode (int fd, int mode)
+{
+  int r = __gl_setmode_check (fd);
+  return r != 0 ? r : __gl_setmode (fd, mode);
+}
+
+/* This macro is obsolescent.  */
+#define SET_BINARY(fd) ((void) set_binary_mode (fd, O_BINARY))
+
 _GL_INLINE_HEADER_END
 
 #endif /* _BINARY_H */

src/emacs.c

@@ -894,9 +894,9 @@ main (int argc, char **argv)
 #endif	/* not SYSTEM_MALLOC and not HYBRID_MALLOC */
 
 #ifdef MSDOS
-  SET_BINARY (fileno (stdin));
+  set_binary_mode (STDIN_FILENO, O_BINARY);
   fflush (stdout);
-  SET_BINARY (fileno (stdout));
+  set_binary_mode (STDOUT_FILENO, O_BINARY);
 #endif /* MSDOS */
 
   /* Skip initial setlocale if LC_ALL is "C", as it's not needed in that case.