warning about gl_SYS_TYPES_H

[Bruno Haible]

When running autogen.sh in GNU gettext, I receive these warnings from autoconf:

configure.ac:155: warning: AC_REQUIRE: `gl_SYS_TYPES_H' was expanded before it 
was required
configure.ac:155: 
http://www.gnu.org/software/autoconf/manual/autoconf.html#Expanded-Before-Required
gnulib-m4/ftello.m4:7: gl_FUNC_FTELLO is expanded from...
gnulib-m4/ftell.m4:7: gl_FUNC_FTELL is expanded from...
gnulib-m4/gnulib-comp.m4:493: gl_INIT is expanded from...
configure.ac:155: the top level
configure.ac:155: warning: AC_REQUIRE: `gl_SYS_TYPES_H' was expanded before it 
was required
configure.ac:155: 
http://www.gnu.org/software/autoconf/manual/autoconf.html#Expanded-Before-Required
gnulib-m4/ftello.m4:7: gl_FUNC_FTELLO is expanded from...
gnulib-m4/ftell.m4:7: gl_FUNC_FTELL is expanded from...
gnulib-m4/gnulib-comp.m4:493: gl_INIT is expanded from...
configure.ac:155: the top level
configure.ac:155: warning: AC_REQUIRE: `gl_SYS_TYPES_H' was expanded before it 
was required
configure.ac:155: 
http://www.gnu.org/software/autoconf/manual/autoconf.html#Expanded-Before-Required
gnulib-m4/ftello.m4:7: gl_FUNC_FTELLO is expanded from...
gnulib-m4/ftell.m4:7: gl_FUNC_FTELL is expanded from...
gnulib-m4/gnulib-comp.m4:493: gl_INIT is expanded from...
configure.ac:155: the top level
configure.ac:155: warning: AC_REQUIRE: `gl_SYS_TYPES_H' was expanded before it 
was required
configure.ac:155: 
http://www.gnu.org/software/autoconf/manual/autoconf.html#Expanded-Before-Required
gnulib-m4/ftello.m4:7: gl_FUNC_FTELLO is expanded from...
gnulib-m4/ftell.m4:7: gl_FUNC_FTELL is expanded from...
gnulib-m4/gnulib-comp.m4:493: gl_INIT is expanded from...
configure.ac:155: the top level
configure.ac:155: warning: AC_REQUIRE: `gl_SYS_TYPES_H' was expanded before it 
was required
configure.ac:155: 
http://www.gnu.org/software/autoconf/manual/autoconf.html#Expanded-Before-Required
gnulib-m4/ftello.m4:7: gl_FUNC_FTELLO is expanded from...
gnulib-m4/ftell.m4:7: gl_FUNC_FTELL is expanded from...
gnulib-m4/gnulib-comp.m4:493: gl_INIT is expanded from...
configure.ac:155: the top level
configure.ac:155: warning: AC_REQUIRE: `gl_SYS_TYPES_H' was expanded before it 
was required
configure.ac:155: 
http://www.gnu.org/software/autoconf/manual/autoconf.html#Expanded-Before-Required
gnulib-m4/ftello.m4:7: gl_FUNC_FTELLO is expanded from...
gnulib-m4/ftell.m4:7: gl_FUNC_FTELL is expanded from...
gnulib-m4/gnulib-comp.m4:493: gl_INIT is expanded from...
configure.ac:155: the top level
configure.ac:155: warning: AC_REQUIRE: `gl_SYS_TYPES_H' was expanded before it 
was required
configure.ac:155: 
http://www.gnu.org/software/autoconf/manual/autoconf.html#Expanded-Before-Required
gnulib-m4/ftello.m4:7: gl_FUNC_FTELLO is expanded from...
gnulib-m4/ftell.m4:7: gl_FUNC_FTELL is expanded from...
gnulib-m4/gnulib-comp.m4:493: gl_INIT is expanded from...
configure.ac:155: the top level

The reason is that gl_SYS_TYPES_H is sometimes required and sometimes invoked:

modules/sys_types:gl_SYS_TYPES_H
m4/fseeko.m4:  AC_REQUIRE([gl_SYS_TYPES_H])
m4/lseek.m4:  AC_REQUIRE([gl_SYS_TYPES_H])
m4/ftello.m4:  AC_REQUIRE([gl_SYS_TYPES_H])

At least in m4/lseek.m4 the AC_REQUIRE is actually needed (for off_t to be
defined in the test program). This patch fixes it.


2013-03-02  Bruno Haible  <address@hidden>

        sys_types: Avoid autoconf warning about gl_SYS_TYPES_H.
        * m4/sys_types_h.m4 (gl_SYS_TYPES_H): Define through AC_DEFUN_ONCE.

--- m4/sys_types_h.m4.orig      Sat Mar  2 17:30:24 2013
+++ m4/sys_types_h.m4   Sat Mar  2 17:25:22 2013
@@ -1,10 +1,10 @@
-# sys_types_h.m4 serial 4
+# sys_types_h.m4 serial 5
 dnl Copyright (C) 2011-2013 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.
 
-AC_DEFUN([gl_SYS_TYPES_H],
+AC_DEFUN_ONCE([gl_SYS_TYPES_H],
 [
   AC_REQUIRE([gl_SYS_TYPES_H_DEFAULTS])
   gl_NEXT_HEADERS([sys/types.h])