Merge from gnulib

* doc/misc/texinfo.tex: Update from gnulib.
* lib/getdtablesize.c, lib/getopt.c, lib/signal.in.h, lib/tempname.c:
* lib/tempname.h, m4/dup2.m4, m4/fcntl.m4, m4/getdtablesize.m4:
Update from gnulib, incorporating:
2015-02-20 getdtablesize: port better for Android
2015-02-19 fcntl: Fix cross compiling
2015-02-18 dup2, fcntl: cross-compile better for Android
2015-02-18 getopt: don't crash on memory exhaustion
2015-02-17 tempname: allow compilation with C++ (trivial)
2015-02-17 dup2, fcntl: port to AIX
2015-02-16 getdtablesize, dup2, fcntl: port to Android
2015-02-11 getdtablesize, signal_h: Fix Android build
2015-02-11 maint: various whitespace cleanups in tempname

11 files changed, 281 insertions, 156 deletions

diff --git a/ChangeLog b/ChangeLog
index 43656680f9c..41bff0ef30a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,19 @@
+2015-02-21  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Merge from gnulib
+        * lib/getdtablesize.c, lib/getopt.c, lib/signal.in.h, lib/tempname.c:
+        * lib/tempname.h, m4/dup2.m4, m4/fcntl.m4, m4/getdtablesize.m4:
+        Update from gnulib, incorporating:
+        2015-02-20 getdtablesize: port better for Android
+        2015-02-19 fcntl: Fix cross compiling
+        2015-02-18 dup2, fcntl: cross-compile better for Android
+        2015-02-18 getopt: don't crash on memory exhaustion
+        2015-02-17 tempname: allow compilation with C++ (trivial)
+        2015-02-17 dup2, fcntl: port to AIX
+        2015-02-16 getdtablesize, dup2, fcntl: port to Android
+        2015-02-11 getdtablesize, signal_h: Fix Android build
+        2015-02-11 maint: various whitespace cleanups in tempname
+
 2015-02-13  Jan Djärv  <jan.h.d@swipnet.se>
 
         * configure.ac: Set locallisppath to empty for NS self contained,
diff --git a/doc/misc/ChangeLog b/doc/misc/ChangeLog
index c796b751f05..d04a8bbb083 100644
--- a/doc/misc/ChangeLog
+++ b/doc/misc/ChangeLog
@@ -1,3 +1,7 @@
+2015-02-21  Paul Eggert  <eggert@cs.ucla.edu>
+
+        * texinfo.tex: Update from gnulib.
+
 2015-02-10  Lars Ingebrigtsen  <larsi@gnus.org>
 
         * eww.texi (Basics): Mention eww-toggle-fonts.
diff --git a/doc/misc/texinfo.tex b/doc/misc/texinfo.tex
index 96b212d2ad1..8236d7d2f82 100644
--- a/doc/misc/texinfo.tex
+++ b/doc/misc/texinfo.tex
@@ -3,7 +3,7 @@
 % Load plain if necessary, i.e., if running under initex.
 \expandafter\ifx\csname fmtname\endcsname\relax\input plain\fi
 %
-\def\texinfoversion{2015-01-31.10}
+\def\texinfoversion{2015-02-05.16}
 %
 % Copyright 1985, 1986, 1988, 1990, 1991, 1992, 1993, 1994, 1995,
 % 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
@@ -4489,7 +4489,6 @@ end
 % Called from \indexdummies and \atdummies.
 %
 \def\commondummies{%
-  %
   % \definedummyword defines \#1 as \string\#1\space, thus effectively
   % preventing its expansion.  This is used only for control words,
   % not control letters, because the \space would be incorrect for
@@ -4566,6 +4565,7 @@ end
   \definedummyword\guilsinglright
   \definedummyword\lbracechar
   \definedummyword\leq
+  \definedummyword\mathopsup
   \definedummyword\minus
   \definedummyword\ogonek
   \definedummyword\pounds
@@ -4579,6 +4579,8 @@ end
   \definedummyword\quotesinglbase
   \definedummyword\rbracechar
   \definedummyword\result
+  \definedummyword\sub
+  \definedummyword\sup
   \definedummyword\textdegree
   %
   % We want to disable all macros so that they are not expanded by \write.
@@ -4653,6 +4655,7 @@ end
   \definedummyword\samp
   \definedummyword\strong
   \definedummyword\tie
+  \definedummyword\U
   \definedummyword\uref
   \definedummyword\url
   \definedummyword\var
@@ -8335,14 +8338,7 @@ end
   \catcode`\\=\other
   %
   % Make the characters 128-255 be printing characters.
-  {%
-    \count1=128
-    \def\loop{%
-      \catcode\count1=\other
-      \advance\count1 by 1
-      \ifnum \count1<256 \loop \fi
-    }%
-  }%
+  {\setnonasciicharscatcodenonglobal\other}%
   %
   % @ is our escape character in .aux files, and we need braces.
   \catcode`\{=1
@@ -9831,15 +9827,51 @@ directory should work if nowhere else does.}
   \DeclareUnicodeCharacter{2261}{\equiv}
 }% end of \utfeightchardefs
 
-
 % US-ASCII character definitions.
 \def\asciichardefs{% nothing need be done
    \relax
 }
 
+% Latin1 (ISO-8859-1) character definitions.
+\def\nonasciistringdefs{%
+  \setnonasciicharscatcode\active
+  \def\defstringchar##1{\def##1{\string##1}}%
+  \defstringchar^^a0\defstringchar^^a1\defstringchar^^a2\defstringchar^^a3%
+  \defstringchar^^a4\defstringchar^^a5\defstringchar^^a6\defstringchar^^a7%
+  \defstringchar^^a8\defstringchar^^a9\defstringchar^^aa\defstringchar^^ab%
+  \defstringchar^^ac\defstringchar^^ad\defstringchar^^ae\defstringchar^^af%
+  %
+  \defstringchar^^b0\defstringchar^^b1\defstringchar^^b2\defstringchar^^b3%
+  \defstringchar^^b4\defstringchar^^b5\defstringchar^^b6\defstringchar^^b7%
+  \defstringchar^^b8\defstringchar^^b9\defstringchar^^ba\defstringchar^^bb%
+  \defstringchar^^bc\defstringchar^^bd\defstringchar^^be\defstringchar^^bf%
+  %
+  \defstringchar^^c0\defstringchar^^c1\defstringchar^^c2\defstringchar^^c3%
+  \defstringchar^^c4\defstringchar^^c5\defstringchar^^c6\defstringchar^^c7%
+  \defstringchar^^c8\defstringchar^^c9\defstringchar^^ca\defstringchar^^cb%
+  \defstringchar^^cc\defstringchar^^cd\defstringchar^^ce\defstringchar^^cf%
+  %
+  \defstringchar^^d0\defstringchar^^d1\defstringchar^^d2\defstringchar^^d3%
+  \defstringchar^^d4\defstringchar^^d5\defstringchar^^d6\defstringchar^^d7%
+  \defstringchar^^d8\defstringchar^^d9\defstringchar^^da\defstringchar^^db%
+  \defstringchar^^dc\defstringchar^^dd\defstringchar^^de\defstringchar^^df%
+  %
+  \defstringchar^^e0\defstringchar^^e1\defstringchar^^e2\defstringchar^^e3%
+  \defstringchar^^e4\defstringchar^^e5\defstringchar^^e6\defstringchar^^e7%
+  \defstringchar^^e8\defstringchar^^e9\defstringchar^^ea\defstringchar^^eb%
+  \defstringchar^^ec\defstringchar^^ed\defstringchar^^ee\defstringchar^^ef%
+  %
+  \defstringchar^^f0\defstringchar^^f1\defstringchar^^f2\defstringchar^^f3%
+  \defstringchar^^f4\defstringchar^^f5\defstringchar^^f6\defstringchar^^f7%
+  \defstringchar^^f8\defstringchar^^f9\defstringchar^^fa\defstringchar^^fb%
+  \defstringchar^^fc\defstringchar^^fd\defstringchar^^fe\defstringchar^^ff%
+}
+
+
 % define all the unicode characters we know about, for the sake of @U.
 \utfeightchardefs
 
+
 % Make non-ASCII characters printable again for compatibility with
 % existing Texinfo documents that may use them, even without declaring a
 % document encoding.
@@ -10193,6 +10225,7 @@ directory should work if nowhere else does.}
 %
 {@catcode`- = @active
  @gdef@normalturnoffactive{%
+   @nonasciistringdefs
    @let-=@normaldash
    @let"=@normaldoublequote
    @let$=@normaldollar %$ font-lock fix
diff --git a/lib/getdtablesize.c b/lib/getdtablesize.c
index 59b97360bc5..bad45f7e32f 100644
--- a/lib/getdtablesize.c
+++ b/lib/getdtablesize.c
@@ -84,32 +84,31 @@ getdtablesize (void)
   return dtablesize;
 }
 
-#elif HAVE_GETDTABLESIZE
+#else
 
+# include <limits.h>
 # include <sys/resource.h>
-# undef getdtablesize
+
+# ifdef __CYGWIN__
+  /* Cygwin 1.7.25 auto-increases the RLIMIT_NOFILE soft limit until it
+     hits the compile-time constant hard limit of 3200.  We might as
+     well just report the hard limit.  */
+#  define rlim_cur rlim_max
+# endif
 
 int
-rpl_getdtablesize(void)
+getdtablesize (void)
 {
-  /* To date, this replacement is only compiled for Cygwin 1.7.25,
-     which auto-increased the RLIMIT_NOFILE soft limit until it
-     hits the compile-time constant hard limit of 3200.  Although
-     that version of cygwin supported a child process inheriting
-     a smaller soft limit, the smaller limit is not enforced, so
-     we might as well just report the hard limit.  */
   struct rlimit lim;
-  if (!getrlimit (RLIMIT_NOFILE, &lim) && lim.rlim_max != RLIM_INFINITY)
-    return lim.rlim_max;
-  return getdtablesize ();
-}
 
-#elif defined _SC_OPEN_MAX
+  if (getrlimit (RLIMIT_NOFILE, &lim) == 0
+      && 0 <= lim.rlim_cur && lim.rlim_cur <= INT_MAX
+      && lim.rlim_cur != RLIM_INFINITY
+      && lim.rlim_cur != RLIM_SAVED_CUR
+      && lim.rlim_cur != RLIM_SAVED_MAX)
+    return lim.rlim_cur;
 
-int
-getdtablesize (void)
-{
-  return sysconf (_SC_OPEN_MAX);
+  return INT_MAX;
 }
 
 #endif
diff --git a/lib/getopt.c b/lib/getopt.c
index 3b9c585a28c..212cbf73410 100644
--- a/lib/getopt.c
+++ b/lib/getopt.c
@@ -487,7 +487,20 @@ _getopt_internal_r (int argc, char **argv, const char *optstring,
         const struct option *p;
         struct option_list *next;
       } *ambig_list = NULL;
+#ifdef _LIBC
+/* malloc() not used for _LIBC to simplify failure messages.  */
+# define free_option_list(l)
+#else
+# define free_option_list(l)                    \
+      while (l != NULL)                         \
+        {                                       \
+          struct option_list *pn = l->next;     \
+          free (l);                             \
+          l = pn;                               \
+        }
+#endif
       int exact = 0;
+      int ambig = 0;
       int indfound = -1;
       int option_index;
 
@@ -514,22 +527,37 @@ _getopt_internal_r (int argc, char **argv, const char *optstring,
                 pfound = p;
                 indfound = option_index;
               }
+            else if (ambig)
+              ; /* Taking simpler path to handling ambiguities.  */
             else if (long_only
                      || pfound->has_arg != p->has_arg
                      || pfound->flag != p->flag
                      || pfound->val != p->val)
               {
                 /* Second or later nonexact match found.  */
+#ifdef _LIBC
+                struct option_list *newp = alloca (sizeof (*newp));
+#else
                 struct option_list *newp = malloc (sizeof (*newp));
-                newp->p = p;
-                newp->next = ambig_list;
-                ambig_list = newp;
+                if (newp == NULL)
+                  {
+                    free_option_list (ambig_list);
+                    ambig_list = NULL;
+                    ambig = 1; /* Use simpler fallback message.  */
+                  }
+                else
+#endif
+                  {
+                    newp->p = p;
+                    newp->next = ambig_list;
+                    ambig_list = newp;
+                  }
               }
           }
 
-      if (ambig_list != NULL && !exact)
+      if ((ambig || ambig_list) && !exact)
         {
-          if (print_errors)
+          if (print_errors && ambig_list)
             {
               struct option_list first;
               first.p = pfound;
@@ -585,18 +613,20 @@ _getopt_internal_r (int argc, char **argv, const char *optstring,
               fputc ('\n', stderr);
 #endif
             }
+          else if (print_errors && ambig)
+            {
+              fprintf (stderr,
+                       _("%s: option '%s' is ambiguous\n"),
+                       argv[0], argv[d->optind]);
+            }
           d->__nextchar += strlen (d->__nextchar);
           d->optind++;
           d->optopt = 0;
+          free_option_list (ambig_list);
           return '?';
         }
 
-      while (ambig_list != NULL)
-        {
-          struct option_list *pn = ambig_list->next;
-          free (ambig_list);
-          ambig_list = pn;
-        }
+      free_option_list (ambig_list);
 
       if (pfound != NULL)
         {
diff --git a/lib/signal.in.h b/lib/signal.in.h
index 0f2ff5af843..265b72ab0ec 100644
--- a/lib/signal.in.h
+++ b/lib/signal.in.h
@@ -55,11 +55,13 @@
 #ifndef _@GUARD_PREFIX@_SIGNAL_H
 #define _@GUARD_PREFIX@_SIGNAL_H
 
-/* Mac OS X 10.3, FreeBSD 6.4, OpenBSD 3.8, OSF/1 4.0, Solaris 2.6 declare
-   pthread_sigmask in <pthread.h>, not in <signal.h>.
+/* Mac OS X 10.3, FreeBSD 6.4, OpenBSD 3.8, OSF/1 4.0, Solaris 2.6, Android
+   declare pthread_sigmask in <pthread.h>, not in <signal.h>.
    But avoid namespace pollution on glibc systems.*/
 #if (@GNULIB_PTHREAD_SIGMASK@ || defined GNULIB_POSIXCHECK) \
-    && ((defined __APPLE__ && defined __MACH__) || defined __FreeBSD__ || defined __OpenBSD__ || defined __osf__ || defined __sun) \
+    && ((defined __APPLE__ && defined __MACH__) \
+        || defined __FreeBSD__ || defined __OpenBSD__ || defined __osf__ \
+        || defined __sun || defined __ANDROID__) \
     && ! defined __GLIBC__
 # include <pthread.h>
 #endif
diff --git a/lib/tempname.c b/lib/tempname.c
index 088b224ab96..8e6d26cc485 100644
--- a/lib/tempname.c
+++ b/lib/tempname.c
@@ -62,6 +62,7 @@
 # define struct_stat64 struct stat64
 #else
 # define struct_stat64 struct stat
+# define __try_tempname try_tempname
 # define __gen_tempname gen_tempname
 # define __getpid getpid
 # define __gettimeofday gettimeofday
@@ -176,21 +177,9 @@ __path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx,
 static const char letters[] =
 "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
 
-/* Generate a temporary file name based on TMPL.  TMPL must match the
-   rules for mk[s]temp (i.e. end in "XXXXXX", possibly with a suffix).
-   The name constructed does not exist at the time of the call to
-   __gen_tempname.  TMPL is overwritten with the result.
-
-   KIND may be one of:
-   __GT_NOCREATE:       simply verify that the name does not exist
-                        at the time of the call.
-   __GT_FILE:           create the file using open(O_CREAT|O_EXCL)
-                        and return a read-write fd.  The file is mode 0600.
-   __GT_DIR:            create a directory, which will be mode 0700.
-
-   We use a clever algorithm to get hard-to-predict names. */
 int
-__gen_tempname (char *tmpl, int suffixlen, int flags, int kind)
+__try_tempname (char *tmpl, int suffixlen, void *args,
+                int (*tryfunc) (char *, void *))
 {
   int len;
   char *XXXXXX;
@@ -199,7 +188,6 @@ __gen_tempname (char *tmpl, int suffixlen, int flags, int kind)
   unsigned int count;
   int fd = -1;
   int save_errno = errno;
-  struct_stat64 st;
 
   /* A lower bound on the number of temporary files to attempt to
      generate.  The maximum total number of temporary file names that
@@ -256,41 +244,7 @@ __gen_tempname (char *tmpl, int suffixlen, int flags, int kind)
       v /= 62;
       XXXXXX[5] = letters[v % 62];
 
-      switch (kind)
-        {
-        case __GT_FILE:
-          fd = __open (tmpl,
-                       (flags & ~O_ACCMODE)
-                       | O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
-          break;
-
-        case __GT_DIR:
-          fd = __mkdir (tmpl, S_IRUSR | S_IWUSR | S_IXUSR);
-          break;
-
-        case __GT_NOCREATE:
-          /* This case is backward from the other three.  __gen_tempname
-             succeeds if __xstat fails because the name does not exist.
-             Note the continue to bypass the common logic at the bottom
-             of the loop.  */
-          if (__lxstat64 (_STAT_VER, tmpl, &st) < 0)
-            {
-              if (errno == ENOENT)
-                {
-                  __set_errno (save_errno);
-                  return 0;
-                }
-              else
-                /* Give up now. */
-                return -1;
-            }
-          continue;
-
-        default:
-          assert (! "invalid KIND in __gen_tempname");
-          abort ();
-        }
-
+      fd = tryfunc (tmpl, args);
       if (fd >= 0)
         {
           __set_errno (save_errno);
@@ -304,3 +258,67 @@ __gen_tempname (char *tmpl, int suffixlen, int flags, int kind)
   __set_errno (EEXIST);
   return -1;
 }
+
+static int
+try_file (char *tmpl, void *flags)
+{
+  int *openflags = flags;
+  return __open (tmpl,
+                 (*openflags & ~O_ACCMODE)
+                 | O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
+}
+
+static int
+try_dir (char *tmpl, void *flags)
+{
+  return __mkdir (tmpl, S_IRUSR | S_IWUSR | S_IXUSR);
+}
+
+static int
+try_nocreate (char *tmpl, void *flags)
+{
+  struct_stat64 st;
+
+  if (__lxstat64 (_STAT_VER, tmpl, &st) == 0)
+    __set_errno (EEXIST);
+  return errno == ENOENT ? 0 : -1;
+}
+
+/* Generate a temporary file name based on TMPL.  TMPL must match the
+   rules for mk[s]temp (i.e. end in "XXXXXX", possibly with a suffix).
+   The name constructed does not exist at the time of the call to
+   __gen_tempname.  TMPL is overwritten with the result.
+
+   KIND may be one of:
+   __GT_NOCREATE:       simply verify that the name does not exist
+                        at the time of the call.
+   __GT_FILE:           create the file using open(O_CREAT|O_EXCL)
+                        and return a read-write fd.  The file is mode 0600.
+   __GT_DIR:            create a directory, which will be mode 0700.
+
+   We use a clever algorithm to get hard-to-predict names. */
+int
+__gen_tempname (char *tmpl, int suffixlen, int flags, int kind)
+{
+  int (*tryfunc) (char *, void *);
+
+  switch (kind)
+    {
+    case __GT_FILE:
+      tryfunc = try_file;
+      break;
+
+    case __GT_DIR:
+      tryfunc = try_dir;
+      break;
+
+    case __GT_NOCREATE:
+      tryfunc = try_nocreate;
+      break;
+
+    default:
+      assert (! "invalid KIND in __gen_tempname");
+      abort ();
+    }
+  return __try_tempname (tmpl, suffixlen, &flags, tryfunc);
+}
diff --git a/lib/tempname.h b/lib/tempname.h
index b560ee5cb14..e6093607463 100644
--- a/lib/tempname.h
+++ b/lib/tempname.h
@@ -32,6 +32,10 @@
 #  define GT_NOCREATE 2
 # endif
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Generate a temporary file name based on TMPL.  TMPL must match the
    rules for mk[s]temp (i.e. end in "XXXXXX", possibly with a suffix).
    The name constructed does not exist at the time of the call to
@@ -47,4 +51,15 @@
    We use a clever algorithm to get hard-to-predict names. */
 extern int gen_tempname (char *tmpl, int suffixlen, int flags, int kind);
 
+/* Similar to gen_tempname, but TRYFUNC is called for each temporary
+   name to try.  If TRYFUNC returns a non-negative number, TRY_GEN_TEMPNAME
+   returns with this value.  Otherwise, if errno is set to EEXIST, another
+   name is tried, or else TRY_GEN_TEMPNAME returns -1. */
+extern int try_tempname (char *tmpl, int suffixlen, void *args,
+                         int (*tryfunc) (char *, void *));
+
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GL_TEMPNAME_H */
diff --git a/m4/dup2.m4 b/m4/dup2.m4
index 0354c6ad478..9aa2ea85ebd 100644
--- a/m4/dup2.m4
+++ b/m4/dup2.m4
@@ -1,4 +1,4 @@
-#serial 20
+#serial 22
 dnl Copyright (C) 2002, 2005, 2007, 2009-2015 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -8,7 +8,6 @@ AC_DEFUN([gl_FUNC_DUP2],
 [
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
   AC_REQUIRE([AC_CANONICAL_HOST])
-  AC_CHECK_FUNCS_ONCE([getdtablesize])
   m4_ifdef([gl_FUNC_DUP2_OBSOLETE], [
     AC_CHECK_FUNCS_ONCE([dup2])
     if test $ac_cv_func_dup2 = no; then
@@ -20,38 +19,44 @@ AC_DEFUN([gl_FUNC_DUP2],
   if test $HAVE_DUP2 = 1; then
     AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works],
       [AC_RUN_IFELSE([
-         AC_LANG_PROGRAM([[#include <unistd.h>
-#include <fcntl.h>
-#include <errno.h>]],
-           [int result = 0;
-#ifdef HAVE_GETDTABLESIZE
-            int bad_fd = getdtablesize ();
-#else
-            int bad_fd = 1000000;
-#endif
-#ifdef FD_CLOEXEC
-            if (fcntl (1, F_SETFD, FD_CLOEXEC) == -1)
-              result |= 1;
-#endif
-            if (dup2 (1, 1) == 0)
-              result |= 2;
-#ifdef FD_CLOEXEC
-            if (fcntl (1, F_GETFD) != FD_CLOEXEC)
-              result |= 4;
-#endif
-            close (0);
-            if (dup2 (0, 0) != -1)
-              result |= 8;
-            /* Many gnulib modules require POSIX conformance of EBADF.  */
-            if (dup2 (2, bad_fd) == -1 && errno != EBADF)
-              result |= 16;
-            /* Flush out some cygwin core dumps.  */
-            if (dup2 (2, -1) != -1 || errno != EBADF)
-              result |= 32;
-            dup2 (2, 255);
-            dup2 (2, 256);
-            return result;
-           ])
+         AC_LANG_PROGRAM(
+           [[#include <errno.h>
+             #include <fcntl.h>
+             #include <limits.h>
+             #include <sys/resource.h>
+             #include <unistd.h>
+           ]],
+           [[int result = 0;
+             int bad_fd = INT_MAX;
+             struct rlimit rlim;
+             if (getrlimit (RLIMIT_NOFILE, &rlim) == 0
+                 && 0 <= rlim.rlim_cur && rlim.rlim_cur <= INT_MAX
+                 && rlim.rlim_cur != RLIM_INFINITY
+                 && rlim.rlim_cur != RLIM_SAVED_MAX
+                 && rlim.rlim_cur != RLIM_SAVED_CUR)
+               bad_fd = rlim.rlim_cur;
+             #ifdef FD_CLOEXEC
+               if (fcntl (1, F_SETFD, FD_CLOEXEC) == -1)
+                 result |= 1;
+             #endif
+             if (dup2 (1, 1) == 0)
+               result |= 2;
+             #ifdef FD_CLOEXEC
+               if (fcntl (1, F_GETFD) != FD_CLOEXEC)
+                 result |= 4;
+             #endif
+             close (0);
+             if (dup2 (0, 0) != -1)
+               result |= 8;
+             /* Many gnulib modules require POSIX conformance of EBADF.  */
+             if (dup2 (2, bad_fd) == -1 && errno != EBADF)
+               result |= 16;
+             /* Flush out some cygwin core dumps.  */
+             if (dup2 (2, -1) != -1 || errno != EBADF)
+               result |= 32;
+             dup2 (2, 255);
+             dup2 (2, 256);
+             return result;]])
         ],
         [gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
         [case "$host_os" in
@@ -59,9 +64,6 @@ AC_DEFUN([gl_FUNC_DUP2],
              gl_cv_func_dup2_works="guessing no" ;;
            cygwin*) # on cygwin 1.5.x, dup2(1,1) returns 0
              gl_cv_func_dup2_works="guessing no" ;;
-           linux*) # On linux between 2008-07-27 and 2009-05-11, dup2 of a
-                   # closed fd may yield -EBADF instead of -1 / errno=EBADF.
-             gl_cv_func_dup2_works="guessing no" ;;
            aix* | freebsd*)
                    # on AIX 7.1 and FreeBSD 6.1, dup2 (1,toobig) gives EMFILE,
                    # not EBADF.
diff --git a/m4/fcntl.m4 b/m4/fcntl.m4
index 733cd2d701b..218e78628ba 100644
--- a/m4/fcntl.m4
+++ b/m4/fcntl.m4
@@ -1,4 +1,4 @@
-# fcntl.m4 serial 5
+# fcntl.m4 serial 7
 dnl Copyright (C) 2009-2015 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -19,7 +19,7 @@ AC_DEFUN([gl_FUNC_FCNTL],
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
   AC_REQUIRE([gl_FCNTL_H_DEFAULTS])
   AC_REQUIRE([AC_CANONICAL_HOST])
-  AC_CHECK_FUNCS_ONCE([fcntl getdtablesize])
+  AC_CHECK_FUNCS_ONCE([fcntl])
   if test $ac_cv_func_fcntl = no; then
     gl_REPLACE_FCNTL
   else
@@ -27,30 +27,34 @@ AC_DEFUN([gl_FUNC_FCNTL],
     dnl haiku alpha 2 F_DUPFD has wrong errno
     AC_CACHE_CHECK([whether fcntl handles F_DUPFD correctly],
       [gl_cv_func_fcntl_f_dupfd_works],
-      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
-#ifdef HAVE_GETDTABLESIZE
-# include <unistd.h>
-#endif
-#include <fcntl.h>
-#include <errno.h>
-]], [[int result = 0;
-#ifdef HAVE_GETDTABLESIZE
-      int bad_fd = getdtablesize ();
-#else
-      int bad_fd = 1000000;
-#endif
-      if (fcntl (0, F_DUPFD, -1) != -1) result |= 1;
-      if (errno != EINVAL) result |= 2;
-      if (fcntl (0, F_DUPFD, bad_fd) != -1) result |= 4;
-      if (errno != EINVAL) result |= 8;
-      return result;
-         ]])],
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <errno.h>
+              #include <fcntl.h>
+              #include <limits.h>
+              #include <sys/resource.h>
+              #include <unistd.h>
+            ]],
+            [[int result = 0;
+              int bad_fd = INT_MAX;
+              struct rlimit rlim;
+              if (getrlimit (RLIMIT_NOFILE, &rlim) == 0
+                  && 0 <= rlim.rlim_cur && rlim.rlim_cur <= INT_MAX
+                  && rlim.rlim_cur != RLIM_INFINITY
+                  && rlim.rlim_cur != RLIM_SAVED_MAX
+                  && rlim.rlim_cur != RLIM_SAVED_CUR)
+                bad_fd = rlim.rlim_cur;
+              if (fcntl (0, F_DUPFD, -1) != -1) result |= 1;
+              if (errno != EINVAL) result |= 2;
+              if (fcntl (0, F_DUPFD, bad_fd) != -1) result |= 4;
+              if (errno != EINVAL) result |= 8;
+              return result;]])],
          [gl_cv_func_fcntl_f_dupfd_works=yes],
          [gl_cv_func_fcntl_f_dupfd_works=no],
-         [# Guess that it works on glibc systems
-          case $host_os in #((
-            *-gnu*) gl_cv_func_fcntl_f_dupfd_works="guessing yes";;
-            *)      gl_cv_func_fcntl_f_dupfd_works="guessing no";;
+         [case $host_os in
+            aix* | cygwin* | haiku*)
+               gl_cv_func_fcntl_f_dupfd_works="guessing no" ;;
+            *) gl_cv_func_fcntl_f_dupfd_works="guessing yes" ;;
           esac])])
     case $gl_cv_func_fcntl_f_dupfd_works in
       *yes) ;;
diff --git a/m4/getdtablesize.m4 b/m4/getdtablesize.m4
index a6b6c1b6c52..25e9968947d 100644
--- a/m4/getdtablesize.m4
+++ b/m4/getdtablesize.m4
@@ -1,4 +1,4 @@
-# getdtablesize.m4 serial 5
+# getdtablesize.m4 serial 6
 dnl Copyright (C) 2008-2015 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -9,7 +9,9 @@ AC_DEFUN([gl_FUNC_GETDTABLESIZE],
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
   AC_REQUIRE([AC_CANONICAL_HOST])
   AC_CHECK_FUNCS_ONCE([getdtablesize])
-  if test $ac_cv_func_getdtablesize = yes; then
+  AC_CHECK_DECLS_ONCE([getdtablesize])
+  if test $ac_cv_func_getdtablesize = yes &&
+     test $ac_cv_have_decl_getdtablesize = yes; then
     # Cygwin 1.7.25 automatically increases the RLIMIT_NOFILE soft limit
     # up to an unchangeable hard limit; all other platforms correctly
     # require setrlimit before getdtablesize() can report a larger value.