[PATCH] fpending: fix regression on DragonFly BSD

[Eric Blake]

Commit 3f5bf99e claimed that it is safe to declare __fpending twice,
but in reality this caused a regression on Dragonfly BSD.  Reported by
GW in <https://lists.gnu.org/archive/html/bug-m4/2013-11/msg00000.html>,
<https://lists.gnu.org/archive/html/bug-gnulib/2013-11/msg00022.html>.

* m4/fpending.m4 (gl_FUNC_FPENDING): Check for declaration.
* lib/fpending.h (__fpending): Don't declare twice.

Signed-off-by: Eric Blake <address@hidden>
---

I tested that this did not regress the Cygwin fix of commit 3f5bf99e,
and am pushing now even though I can't easily test that it fixes the
DragonFly issue.

 ChangeLog      |  8 ++++++++
 lib/fpending.h |  2 +-
 m4/fpending.m4 | 18 +++++++++++-------
 3 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 3d0f0fe..976c624 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2013-11-08  Eric Blake  <address@hidden>
+
+       fpending: fix regression on DragonFly BSD
+       * m4/fpending.m4 (gl_FUNC_FPENDING): Check for declaration.
+       * lib/fpending.h (__fpending): Don't declare twice.
+       Reported by GW in
+       <https://lists.gnu.org/archive/html/bug-m4/2013-11/msg00000.html>
+
 2013-11-05  Jim Meyering  <address@hidden>

        hash: relax license to LGPLv2+, for libguestfs
diff --git a/lib/fpending.h b/lib/fpending.h
index 30d67fc..c12871d 100644
--- a/lib/fpending.h
+++ b/lib/fpending.h
@@ -24,6 +24,6 @@
 # include <stdio_ext.h>
 #endif

-#ifndef __fpending
+#if !HAVE_DECL_FPENDING
 size_t __fpending (FILE *) _GL_ATTRIBUTE_PURE;
 #endif
diff --git a/m4/fpending.m4 b/m4/fpending.m4
index c8d9e8b..669105b 100644
--- a/m4/fpending.m4
+++ b/m4/fpending.m4
@@ -1,4 +1,4 @@
-# serial 20
+# serial 21

 # Copyright (C) 2000-2001, 2004-2013 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
@@ -16,19 +16,23 @@ dnl we have to grub around in the FILE struct.
 AC_DEFUN([gl_FUNC_FPENDING],
 [
   AC_CHECK_HEADERS_ONCE([stdio_ext.h])
+  fp_headers='
+    #include <stdio.h>
+    #if HAVE_STDIO_EXT_H
+    # include <stdio_ext.h>
+    #endif
+  '
   AC_CACHE_CHECK([for __fpending], [gl_cv_func___fpending],
     [
       AC_LINK_IFELSE(
-        [AC_LANG_PROGRAM(
-           [[#include <stdio.h>
-             #if HAVE_STDIO_EXT_H
-             # include <stdio_ext.h>
-             #endif
-           ]],
+        [AC_LANG_PROGRAM([$fp_headers],
            [[return ! __fpending (stdin);]])],
         [gl_cv_func___fpending=yes],
         [gl_cv_func___fpending=no])
     ])
+  if test $gl_cv_func___fpending = yes; then
+    AC_CHECK_DECLS([__fpending], [], [], [$fp_headers])
+  fi
 ])

 AC_DEFUN([gl_PREREQ_FPENDING],
-- 
1.8.3.1