error: avoid expand-before-require warning

* modules/errno (configure.ac): Require, rather than expand,
gl_HEADER_ERRNO_H.
* m4/errno_h.m4 (gl_HEADER_ERRNO_H_BODY): Merge...
(gl_HEADER_ERRNO_H): ...into this macro, and use AC_DEFUN_ONCE to
enforce that all clients require it.

Signed-off-by: Eric Blake <ebb9@byu.net>

diff --git a/ChangeLog b/ChangeLog
index 7b7c8bd..bc8fc9f 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2009-01-21  Eric Blake  <ebb9@byu.net>
 
+       error: avoid expand-before-require warning
+       * modules/errno (configure.ac): Require, rather than expand,
+       gl_HEADER_ERRNO_H.
+       * m4/errno_h.m4 (gl_HEADER_ERRNO_H_BODY): Merge...
+       (gl_HEADER_ERRNO_H): ...into this macro, and use AC_DEFUN_ONCE to
+       enforce that all clients require it.
+
        gnulib-tool: avoid warnings from using obsolete AC_GNU_SOURCE
        * gnulib-tool (func_dest_tmpfilename, func_create_testdir): Using
        obsolete AC_GNU_SOURCE causes out-of-order expansion; avoid it,

diff --git a/m4/errno_h.m4 b/m4/errno_h.m4
index 0682d1a..4d77672 100644 (file)
--- a/m4/errno_h.m4
+++ b/m4/errno_h.m4
@@ -1,17 +1,11 @@
-# errno_h.m4 serial 3
+# errno_h.m4 serial 4
 dnl Copyright (C) 2004, 2006, 2008, 2009 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_HEADER_ERRNO_H],
-[
-  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
-  dnl once only, before all statements that occur in other macros.
-  AC_REQUIRE([gl_HEADER_ERRNO_H_BODY])
-])
-
-AC_DEFUN([gl_HEADER_ERRNO_H_BODY],
+dnl This macro must pass through AC_REQUIRE (never directly invoke it).
+AC_DEFUN_ONCE([gl_HEADER_ERRNO_H],
 [
   AC_REQUIRE([AC_PROG_CC])
   AC_CACHE_CHECK([for complete errno.h], [gl_cv_header_errno_h_complete], [

diff --git a/modules/errno b/modules/errno
index 8806621..208636d 100644 (file)
--- a/modules/errno
+++ b/modules/errno
@@ -9,7 +9,7 @@ Depends-on:
 include_next
 
 configure.ac:
-gl_HEADER_ERRNO_H
+AC_REQUIRE([gl_HEADER_ERRNO_H])
 
 Makefile.am:
 BUILT_SOURCES += $(ERRNO_H)