--- a/ChangeLog	Sun Sep 28 16:07:52 2008 +0200
+++ b/ChangeLog	Sun Sep 28 16:12:20 2008 +0200
@@ -1,3 +1,12 @@
+2008-09-28  Bruno Haible  <bruno@clisp.org>
+
+	Override fopen more carefully.
+	* lib/fopen.c (orig_fopen): New function.
+	(rpl_fopen): Use orig_fopen instead of open.
+	* m4/fopen.m4 (gl_PREREQ_FOPEN): New macro.
+	(gl_FUNC_FOPEN): Invoke it.
+	Needed on AIX. Reported by Rainer Tammer <tammer@tammer.net>.
+
 2008-09-28  Bruno Haible  <bruno@clisp.org>
 
 	* lib/pipe.h (create_pipe_out, create_pipe_bidi): Add comment about

--- a/lib/fopen.c	Sun Sep 28 16:07:52 2008 +0200
+++ b/lib/fopen.c	Sun Sep 28 16:12:20 2008 +0200
@@ -18,6 +18,17 @@
 
 #include <config.h>
 
+/* Get the original definition of fopen.  It might be defined as a macro.  */
+#define __need_FILE
+#include <stdio.h>
+#undef __need_FILE
+
+static inline FILE *
+orig_fopen (const char *filename, const char *mode)
+{
+  return fopen (filename, mode);
+}
+
 /* Specification.  */
 #include <stdio.h>
 
@@ -28,7 +39,6 @@
 
 FILE *
 rpl_fopen (const char *filename, const char *mode)
-#undef fopen
 {
 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
   if (strcmp (filename, "/dev/null") == 0)
@@ -89,5 +99,5 @@
   }
 # endif
 
-  return fopen (filename, mode);
+  return orig_fopen (filename, mode);
 }

--- a/m4/fopen.m4	Sun Sep 28 16:07:52 2008 +0200
+++ b/m4/fopen.m4	Sun Sep 28 16:12:20 2008 +0200
@@ -1,4 +1,4 @@
-# fopen.m4 serial 2
+# fopen.m4 serial 3
 dnl Copyright (C) 2007-2008 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -43,8 +43,15 @@
             [Define to 1 if fopen() fails to recognize a trailing slash.])
           REPLACE_FOPEN=1
           AC_LIBOBJ([fopen])
+          gl_PREREQ_FOPEN
           ;;
       esac
       ;;
   esac
 ])
+
+# Prerequisites of lib/fopen.c.
+AC_DEFUN([gl_PREREQ_FOPEN],
+[
+  AC_REQUIRE([AC_C_INLINE])
+])