--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2010-12-19  Bruno Haible  <bruno@clisp.org>
+
+	fseeko: Add missing declaration on OSF/1 5.1.
+	* lib/stdio.in.h (fseeko): Test HAVE_DECL_FSEEKO, not HAVE_FSEEKO.
+	* m4/fseeko.m4 (gl_FUNC_FSEEKO): Test whether fseeko is declared.
+	* m4/stdio_h.m4 (gl_STDIO_H_DEFAULTS): Initialize HAVE_DECL_FSEEKO.
+	* modules/stdio (Makefile.am): Substitute HAVE_DECL_FSEEKO.
+	* doc/posix-functions/fseeko.texi: Mention the OSF/1 5.1 problem.
+
 2010-12-19  Bruno Haible  <bruno@clisp.org>
 
 	fchdir: Add missing declaration on OSF/1 5.1.

--- a/doc/posix-functions/fseeko.texi
+++ b/doc/posix-functions/fseeko.texi
@@ -13,7 +13,8 @@
 IRIX 5.3, OSF/1 4.0, Solaris 2.5.1, mingw.
 @item
 The declaration of @code{fseeko} in @code{<stdio.h>} is not enabled by default
-on some platforms: glibc 2.3.6.
+on some platforms:
+glibc 2.3.6, OSF/1 5.1.
 @item
 This function fails on seekable stdin, stdout, and stderr: cygwin <= 1.5.24.
 @end itemize

--- a/lib/stdio.in.h
+++ b/lib/stdio.in.h
@@ -345,7 +345,7 @@
                                _GL_ARG_NONNULL ((1)));
 _GL_CXXALIAS_RPL (fseeko, int, (FILE *fp, off_t offset, int whence));
 # else
-#  if ! @HAVE_FSEEKO@
+#  if ! @HAVE_DECL_FSEEKO@
 _GL_FUNCDECL_SYS (fseeko, int, (FILE *fp, off_t offset, int whence)
                                _GL_ARG_NONNULL ((1)));
 #  endif

--- a/m4/fseeko.m4
+++ b/m4/fseeko.m4
@@ -1,4 +1,4 @@
-# fseeko.m4 serial 9
+# fseeko.m4 serial 10
 dnl Copyright (C) 2007-2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -10,6 +10,11 @@
   AC_REQUIRE([gl_HAVE_FSEEKO])
   AC_REQUIRE([gl_STDIN_LARGE_OFFSET])
 
+  AC_CHECK_DECLS_ONCE([fseeko])
+  if test $ac_cv_have_decl_fseeko = no; then
+    HAVE_DECL_FSEEKO=0
+  fi
+
   if test $gl_cv_func_fseeko = no; then
     HAVE_FSEEKO=0
     gl_REPLACE_FSEEKO

--- a/m4/stdio_h.m4
+++ b/m4/stdio_h.m4
@@ -1,4 +1,4 @@
-# stdio_h.m4 serial 31
+# stdio_h.m4 serial 32
 dnl Copyright (C) 2007-2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -95,6 +95,7 @@
   GNULIB_VSPRINTF_POSIX=0;       AC_SUBST([GNULIB_VSPRINTF_POSIX])
   dnl Assume proper GNU behavior unless another module says otherwise.
   HAVE_DECL_FPURGE=1;            AC_SUBST([HAVE_DECL_FPURGE])
+  HAVE_DECL_FSEEKO=1;            AC_SUBST([HAVE_DECL_FSEEKO])
   HAVE_DECL_GETDELIM=1;          AC_SUBST([HAVE_DECL_GETDELIM])
   HAVE_DECL_GETLINE=1;           AC_SUBST([HAVE_DECL_GETLINE])
   HAVE_DECL_OBSTACK_PRINTF=1;    AC_SUBST([HAVE_DECL_OBSTACK_PRINTF])

--- a/modules/stdio
+++ b/modules/stdio
@@ -73,6 +73,7 @@
 	      -e 's|@''GNULIB_VSPRINTF_POSIX''@|$(GNULIB_VSPRINTF_POSIX)|g' \
 	      < $(srcdir)/stdio.in.h | \
 	  sed -e 's|@''HAVE_DECL_FPURGE''@|$(HAVE_DECL_FPURGE)|g' \
+	      -e 's|@''HAVE_DECL_FSEEKO''@|$(HAVE_DECL_FSEEKO)|g' \
 	      -e 's|@''HAVE_DECL_GETDELIM''@|$(HAVE_DECL_GETDELIM)|g' \
 	      -e 's|@''HAVE_DECL_GETLINE''@|$(HAVE_DECL_GETLINE)|g' \
 	      -e 's|@''HAVE_DECL_OBSTACK_PRINTF''@|$(HAVE_DECL_OBSTACK_PRINTF)|g' \