As of this morning, autoconf.git now warns you on instances of expand-before-
require (aka ordering bugs in older autoconf, and redundant output when using
bleeding edge autoconf). I'm working on a series of patches to reduce the
number of warnings we trigger, starting with this one:
configure.ac:33: warning: AC_REQUIRE: `AC_USE_SYSTEM_EXTENSIONS' was expanded
before it was required
m4/extensions.m4:93: gl_USE_SYSTEM_EXTENSIONS is expanded from...
m4/gnulib-comp.m4:21: gl_EARLY is expanded from...
configure.ac:33: the top level
configure.ac:33: warning: AC_COMPILE_IFELSE was called before
AC_USE_SYSTEM_EXTENSIONS
m4/extensions.m4:23: AC_USE_SYSTEM_EXTENSIONS is expanded from...
configure.ac:33: warning: AC_RUN_IFELSE was called before
AC_USE_SYSTEM_EXTENSIONS
My analysis: gl_EARLY does the following:
AC_REQUIRE([AC_GNU_SOURCE])
AB_INIT
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
but AC_GNU_SOURCE expands, rather than requires, AC_USE_SYSTEM_EXTENSIONS, such
that the later gl_USE_SYSTEM_EXTENSIONS, which requires
AC_USE_SYSTEM_EXTENSIONS. I can probably address some of this by changing
AU_DEFUN in autoconf, such that autoupdate handles a macro differently than
autoconf; but that will only affect autoconf 2.64+. For autoconf 2.63, this
means that we truly have an out-of-order expansion situation. For even earlier
autoconf, such as 2.59, AC_GNU_SOURCE did not require AC_USE_SYSTEM_EXTENSIONS,
so there is no ordering dependency there; however, gnulib ALREADY provides a
working AC_USE_SYSTEM_EXTENSIONS, even for autoconf 2.59. Therefore, I see no
reason for us to even worry about using AC_GNU_SOURCE.
Besides, the only use of AC_GNU_SOURCE in current gnulib sources is in
m4/threadlib.m4, but that is from gettext, and is already coded to use
AC_GNU_SOURCE only if AC_USE_SYSTEM_EXTENSIONS is not available, because Bruno
didn't want that file to suck in gl_USE_SYSTEM_EXTENSIONS.
Therefore, I'm committing this patch (I love it when pure deletion fixes a bug,
and makes gnulib-tool fork fewer times to boot):
From: Eric Blake <e...@byu.net>
Date: Wed, 21 Jan 2009 09:55:55 -0700
Subject: [PATCH] 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,
and rely solely on gl_USE_SYSTEM_EXTENSIONS.
Signed-off-by: Eric Blake <e...@byu.net>
---
ChangeLog | 7 +++++++
gnulib-tool | 11 -----------
2 files changed, 7 insertions(+), 11 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index af6bee5..7b7c8bd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2009-01-21 Eric Blake <e...@byu.net>
+
+ 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,
+ and rely solely on gl_USE_SYSTEM_EXTENSIONS.
+
2009-01-21 Paolo Bonzini <bonz...@gnu.org>
Revert:
diff --git a/gnulib-tool b/gnulib-tool
index c11ef35..c6725d3 100755
--- a/gnulib-tool
+++ b/gnulib-tool
@@ -3378,9 +3378,6 @@ s,//*$,/,'
if test -n "$uses_subdirs"; then
echo " AC_REQUIRE([AM_PROG_CC_C_O])"
fi
- if grep AC_GNU_SOURCE "$destdir"/$m4base/*.m4 >/dev/null 2>/dev/null; then
- echo " AC_REQUIRE([AC_GNU_SOURCE])"
- fi
for module in $final_modules; do
func_verify_module
if test -n "$module"; then
@@ -3919,10 +3916,6 @@ func_create_testdir ()
echo "AC_PROG_MAKE_SET"
echo "AC_PROG_RANLIB"
echo
- if grep AC_GNU_SOURCE "$testdir/$m4base"/*.m4 >/dev/null 2>/dev/null; then
- echo "AC_GNU_SOURCE"
- echo
- fi
for module in $modules; do
func_verify_module
if test -n "$module"; then
@@ -4052,10 +4045,6 @@ func_create_testdir ()
echo "AM_PROG_CC_C_O"
echo
fi
- if grep AC_GNU_SOURCE "$testdir/$m4base"/*.m4 >/dev/null 2>/dev/null; then
- echo "AC_GNU_SOURCE"
- echo
- fi
for module in $modules; do
func_verify_nontests_module
if test -n "$module"; then
--
1.6.0.4
