Fix data-loss with --batch.

* admin/merge-gnulib (GNULIB_MODULES): Add close-stream.
* lib/close-stream.c, lib/close-stream.h, lib/fpending.c
* lib/fpending.h, m4/close-stream.m4, m4/fpending.m4:
New files, from gnulib.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
* src/emacs.c: Include <close-stream.h>.
(close_output_streams): New function.
(main): Pass it to atexit, so that Emacs closes stdout and stderr
and handles errors appropriately.
(Fkill_emacs): Don't worry about flushing, as close_output_stream
does that now.

Fixes: debbugs:9574

3 files changed, 116 insertions, 0 deletions

diff --git a/m4/close-stream.m4 b/m4/close-stream.m4
new file mode 100644
index 00000000000..be0c8a22979
--- /dev/null
+++ b/m4/close-stream.m4
@@ -0,0 +1,11 @@
+#serial 4
+dnl Copyright (C) 2006-2007, 2009-2012 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Prerequisites of lib/close-stream.c.
+AC_DEFUN([gl_CLOSE_STREAM],
+[
+  :
+])
diff --git a/m4/fpending.m4 b/m4/fpending.m4
new file mode 100644
index 00000000000..33a5c94c3a3
--- /dev/null
+++ b/m4/fpending.m4
@@ -0,0 +1,90 @@
+# serial 19
+
+# Copyright (C) 2000-2001, 2004-2012 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+dnl From Jim Meyering
+dnl Using code from emacs, based on suggestions from Paul Eggert
+dnl and Ulrich Drepper.
+
+dnl Find out how to determine the number of pending output bytes on a stream.
+dnl glibc (2.1.93 and newer) and Solaris provide __fpending.  On other systems,
+dnl we have to grub around in the FILE struct.
+
+AC_DEFUN([gl_FUNC_FPENDING],
+[
+  AC_CHECK_HEADERS_ONCE([stdio_ext.h])
+  AC_CHECK_FUNCS_ONCE([__fpending])
+  fp_headers='
+#     include <stdio.h>
+#     if HAVE_STDIO_EXT_H
+#      include <stdio_ext.h>
+#     endif
+'
+  AC_CHECK_DECLS([__fpending], , , $fp_headers)
+])
+
+AC_DEFUN([gl_PREREQ_FPENDING],
+[
+  AC_CACHE_CHECK(
+              [how to determine the number of pending output bytes on a stream],
+                 ac_cv_sys_pending_output_n_bytes,
+    [
+      for ac_expr in                                                    \
+                                                                        \
+          '# glibc2'                                                    \
+          'fp->_IO_write_ptr - fp->_IO_write_base'                      \
+                                                                        \
+          '# traditional Unix'                                          \
+          'fp->_ptr - fp->_base'                                        \
+                                                                        \
+          '# BSD'                                                       \
+          'fp->_p - fp->_bf._base'                                      \
+                                                                        \
+          '# SCO, Unixware'                                             \
+          '(fp->__ptr ? fp->__ptr - fp->__base : 0)'                    \
+                                                                        \
+          '# QNX'                                                       \
+          '(fp->_Mode & 0x2000 /*_MWRITE*/ ? fp->_Next - fp->_Buf : 0)' \
+                                                                        \
+          '# old glibc?'                                                \
+          'fp->__bufp - fp->__buffer'                                   \
+                                                                        \
+          '# old glibc iostream?'                                       \
+          'fp->_pptr - fp->_pbase'                                      \
+                                                                        \
+          '# emx+gcc'                                                   \
+          'fp->_ptr - fp->_buffer'                                      \
+                                                                        \
+          '# Minix'                                                     \
+          'fp->_ptr - fp->_buf'                                         \
+                                                                        \
+          '# Plan9'                                                     \
+          'fp->wp - fp->buf'                                            \
+                                                                        \
+          '# VMS'                                                       \
+          '(*fp)->_ptr - (*fp)->_base'                                  \
+                                                                        \
+          '# e.g., DGUX R4.11; the info is not available'               \
+          1                                                             \
+          ; do
+
+        # Skip each embedded comment.
+        case "$ac_expr" in '#'*) continue;; esac
+
+        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>]],
+          [[FILE *fp = stdin; (void) ($ac_expr);]])],
+          [fp_done=yes]
+        )
+        test "$fp_done" = yes && break
+      done
+
+      ac_cv_sys_pending_output_n_bytes=$ac_expr
+    ]
+  )
+  AC_DEFINE_UNQUOTED([PENDING_OUTPUT_N_BYTES],
+    $ac_cv_sys_pending_output_n_bytes,
+    [the number of pending output bytes on stream 'fp'])
+])
diff --git a/m4/gnulib-comp.m4 b/m4/gnulib-comp.m4
index de2355d87c3..5cd278454e7 100644
--- a/m4/gnulib-comp.m4
+++ b/m4/gnulib-comp.m4
@@ -44,6 +44,7 @@ AC_DEFUN([gl_EARLY],
   # Code from module c-strcase:
   # Code from module careadlinkat:
   # Code from module clock-time:
+  # Code from module close-stream:
   # Code from module crypto/md5:
   # Code from module crypto/sha1:
   # Code from module crypto/sha256:
@@ -58,6 +59,7 @@ AC_DEFUN([gl_EARLY],
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
   # Code from module extern-inline:
   # Code from module filemode:
+  # Code from module fpending:
   # Code from module getloadavg:
   # Code from module getopt-gnu:
   # Code from module getopt-posix:
@@ -141,6 +143,8 @@ AC_DEFUN([gl_INIT],
   gl_FUNC_ALLOCA
   AC_CHECK_FUNCS_ONCE([readlinkat])
   gl_CLOCK_TIME
+  gl_CLOSE_STREAM
+  gl_MODULE_INDICATOR([close-stream])
   gl_MD5
   gl_SHA1
   gl_SHA256
@@ -157,6 +161,11 @@ AC_DEFUN([gl_INIT],
   gl_EXECINFO_H
   AC_REQUIRE([gl_EXTERN_INLINE])
   gl_FILEMODE
+  gl_FUNC_FPENDING
+  if test $ac_cv_func___fpending = no; then
+    AC_LIBOBJ([fpending])
+    gl_PREREQ_FPENDING
+  fi
   gl_GETLOADAVG
   if test $HAVE_GETLOADAVG = 0; then
     AC_LIBOBJ([getloadavg])
@@ -534,6 +543,8 @@ AC_DEFUN([gl_FILE_LIST], [
   lib/c-strncasecmp.c
   lib/careadlinkat.c
   lib/careadlinkat.h
+  lib/close-stream.c
+  lib/close-stream.h
   lib/dosname.h
   lib/dtoastr.c
   lib/dtotimespec.c
@@ -542,6 +553,8 @@ AC_DEFUN([gl_FILE_LIST], [
   lib/execinfo.in.h
   lib/filemode.c
   lib/filemode.h
+  lib/fpending.c
+  lib/fpending.h
   lib/ftoastr.c
   lib/ftoastr.h
   lib/getloadavg.c
@@ -609,12 +622,14 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/alloca.m4
   m4/c-strtod.m4
   m4/clock_time.m4
+  m4/close-stream.m4
   m4/dup2.m4
   m4/environ.m4
   m4/execinfo.m4
   m4/extensions.m4
   m4/extern-inline.m4
   m4/filemode.m4
+  m4/fpending.m4
   m4/getloadavg.m4
   m4/getopt.m4
   m4/gettime.m4