Re: gettext 0.18.1: fallback for AC_USE_SYSTEM_EXTENSIONS in fcntl-o.m4

[Bruno Haible]

[CCing bug-gnulib]

Hi Christian,

Christian Weisgerber wrote in
<http://lists.gnu.org/archive/html/bug-gnu-utils/2010-07/msg00000.html>:
> Pulling in the new AM_GNU_GETTEXT macro from gettext 0.18.1 causes
> errors with older versions of autoconf, such as 2.59, because
> AC_USE_SYSTEM_EXTENSIONS is required but not defined.  The requirement
> originates in fcntl-o.m4.  Maybe it is possible to fallback to
> AC_GNU_SOURCE there as is done in threadlib.m4.
> 
> 
> --- gettext-runtime/m4/fcntl-o.m4.orig        Thu Jul  1 07:44:09 2010
> +++ gettext-runtime/m4/fcntl-o.m4     Thu Jul  1 07:44:43 2010
> @@ -12,7 +12,9 @@ dnl Written by Paul Eggert.
>  AC_DEFUN([gl_FCNTL_O_FLAGS],
>  [
>    dnl Persuade glibc <fcntl.h> to define O_NOATIME and O_NOFOLLOW.
> -  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
> +  m4_ifdef([AC_USE_SYSTEM_EXTENSIONS],
> +    [AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])],
> +    [AC_REQUIRE([AC_GNU_SOURCE])])
>    AC_CACHE_CHECK([for working fcntl.h], [gl_cv_header_working_fcntl_h],
>      [AC_RUN_IFELSE(
>         [AC_LANG_PROGRAM(

Thanks for the report and patch. I'm applying it with the same comment as
in threadlib.m4:


2010-07-01  Christian Weisgerber  <address@hidden>  (tiny change)

        gettext: Use AC_GNU_SOURCE as a fallback for AC_USE_SYSTEM_EXTENSIONS.
        * m4/fcntl-o.m4 (gl_FCNTL_O_FLAGS): When AC_USE_SYSTEM_EXTENSIONS is
        not present (i.e. with autoconf 2.59 and when using gettextize, not
        gnulib), require AC_GNU_SOURCE instead.

--- m4/fcntl-o.m4.orig  Thu Jul  1 11:02:52 2010
+++ m4/fcntl-o.m4       Thu Jul  1 11:02:34 2010
@@ -1,4 +1,4 @@
-# fcntl-o.m4 serial 1
+# fcntl-o.m4 serial 2
 dnl Copyright (C) 2006, 2009-2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -12,7 +12,11 @@
 AC_DEFUN([gl_FCNTL_O_FLAGS],
 [
   dnl Persuade glibc <fcntl.h> to define O_NOATIME and O_NOFOLLOW.
-  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+  dnl AC_USE_SYSTEM_EXTENSIONS was introduced in autoconf 2.60 and obsoletes
+  dnl AC_GNU_SOURCE.
+  m4_ifdef([AC_USE_SYSTEM_EXTENSIONS],
+    [AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])],
+    [AC_REQUIRE([AC_GNU_SOURCE])])
   AC_CACHE_CHECK([for working fcntl.h], [gl_cv_header_working_fcntl_h],
     [AC_RUN_IFELSE(
        [AC_LANG_PROGRAM(