source: trunk/essentials/sys-devel/automake-1.7/m4/auxdir.m4

Last change on this file was 3120, checked in by bird, 18 years ago

automake 1.7.9

File size: 2.8 KB
Line 
1# AM_AUX_DIR_EXPAND
2
3# Copyright 2001 Free Software Foundation, Inc.
4
5# This program is free software; you can redistribute it and/or modify
6# it under the terms of the GNU General Public License as published by
7# the Free Software Foundation; either version 2, or (at your option)
8# any later version.
9
10# This program is distributed in the hope that it will be useful,
11# but WITHOUT ANY WARRANTY; without even the implied warranty of
12# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13# GNU General Public License for more details.
14
15# You should have received a copy of the GNU General Public License
16# along with this program; if not, write to the Free Software
17# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
18# 02111-1307, USA.
19
20# For projects using AC_CONFIG_AUX_DIR([foo]), Autoconf sets
21# $ac_aux_dir to `$srcdir/foo'. In other projects, it is set to
22# `$srcdir', `$srcdir/..', or `$srcdir/../..'.
23#
24# Of course, Automake must honor this variable whenever it calls a
25# tool from the auxiliary directory. The problem is that $srcdir (and
26# therefore $ac_aux_dir as well) can be either absolute or relative,
27# depending on how configure is run. This is pretty annoying, since
28# it makes $ac_aux_dir quite unusable in subdirectories: in the top
29# source directory, any form will work fine, but in subdirectories a
30# relative path needs to be adjusted first.
31#
32# $ac_aux_dir/missing
33# fails when called from a subdirectory if $ac_aux_dir is relative
34# $top_srcdir/$ac_aux_dir/missing
35# fails if $ac_aux_dir is absolute,
36# fails when called from a subdirectory in a VPATH build with
37# a relative $ac_aux_dir
38#
39# The reason of the latter failure is that $top_srcdir and $ac_aux_dir
40# are both prefixed by $srcdir. In an in-source build this is usually
41# harmless because $srcdir is `.', but things will broke when you
42# start a VPATH build or use an absolute $srcdir.
43#
44# So we could use something similar to $top_srcdir/$ac_aux_dir/missing,
45# iff we strip the leading $srcdir from $ac_aux_dir. That would be:
46# am_aux_dir='\$(top_srcdir)/'`expr "$ac_aux_dir" : "$srcdir//*\(.*\)"`
47# and then we would define $MISSING as
48# MISSING="\${SHELL} $am_aux_dir/missing"
49# This will work as long as MISSING is not called from configure, because
50# unfortunately $(top_srcdir) has no meaning in configure.
51# However there are other variables, like CC, which are often used in
52# configure, and could therefore not use this "fixed" $ac_aux_dir.
53#
54# Another solution, used here, is to always expand $ac_aux_dir to an
55# absolute PATH. The drawback is that using absolute paths prevent a
56# configured tree to be moved without reconfiguration.
57
58# Rely on autoconf to set up CDPATH properly.
59AC_PREREQ([2.50])
60
61AC_DEFUN([AM_AUX_DIR_EXPAND], [
62# expand $ac_aux_dir to an absolute path
63am_aux_dir=`cd $ac_aux_dir && pwd`
64])
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