AX_ENABLE_BUILDDIR [(dirstring-or-command [,Makefile.mk [,-all]])]
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.
$1 = $host (overridden with $HOST) $2 = Makefile.mk $3 = -all
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
which can of course set at configure time as well using
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.
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 gives unlimited permission to copy, distribute and modify the configure scripts that are the output of Autoconf when processing the Macro. You need not follow the terms of the GNU General Public License when using or distributing such scripts, even though portions of the text of the Macro appear in them. The GNU General Public License (GPL) does govern all other use of the material that constitutes the Autoconf Macro.
This special exception to the GPL applies to versions of the Autoconf Macro released by the Autoconf Archive. When you make and distribute a modified version of the Autoconf Macro, you may extend this special exception to the GPL to apply to your modified version as well.