@node ax_enable_builddir
@unnumberedsec ax_enable_builddir

@majorheading Synopsis

@smallexample
AX_ENABLE_BUILDDIR [(dirstring-or-command [,Makefile.mk [,-all]])]
@end smallexample

@majorheading Description

If the current configure was run within the srcdir then we move all
configure-files into a subdir and let the configure steps continue
there. We provide an option --disable-builddir to suppress the move into
a separate builddir.

Defaults:

@smallexample
  $1 = $host (overridden with $HOST)
  $2 = Makefile.mk
  $3 = -all
@end smallexample

This macro must be called before AM_INIT_AUTOMAKE. It creates a default
toplevel srcdir Makefile from the information found in the created
toplevel builddir Makefile. It just copies the variables and
rule-targets, each extended with a default rule-execution that recurses
into the build directory of the current "HOST". You can override the
auto-detection through `config.guess` and build-time of course, as in

@smallexample
  make HOST=i386-mingw-cross
@end smallexample

which can of course set at configure time as well using

@smallexample
  configure --host=i386-mingw-cross
@end smallexample

After the default has been created, additional rules can be appended
that will not just recurse into the subdirectories and only ever exist
in the srcdir toplevel makefile - these parts are read from the $2 =
Makefile.mk file

The automatic rules are usually scanning the toplevel Makefile for lines
like '#### $host |$builddir' to recognize the place where to recurse
into. Usually, the last one is the only one used. However, almost all
targets have an additional "*-all" rule which makes the script to
recurse into _all_ variants of the current HOST (!!) setting. The "-all"
suffix can be overridden for the macro as well.

a special rule is only given for things like "dist" that will copy the
tarball from the builddir to the sourcedir (or $(PUB)) for reason of
convenience.

@majorheading Source Code

Download the
@uref{http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=blob_plain;f=m4/ax_enable_builddir.m4,latest
version of @file{ax_enable_builddir.m4}} or browse
@uref{http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=history;f=m4/ax_enable_builddir.m4,the
macro's revision history}.

@majorheading License

@w{Copyright @copyright{} 2009 Guido U. Draheim @email{guidod@@gmx.de}} @* @w{Copyright @copyright{} 2009 Alan Jenkins @email{alan-jenkins@@tuffmail.co.uk}}

This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3 of the License, or (at your
option) any later version.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
Public License for more details.

You should have received a copy of the GNU General Public License along
with this program. If not, see <https://www.gnu.org/licenses/>.

As a special exception, the respective Autoconf Macro's copyright owner
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