Reconf Option

When the version of Autotools applications installed on the host conflicts with the version of tools that generated library's building infrastructure, build process fails with the following error message.

configure.ac:7: error: version mismatch.  This is Automake 1.15.1,
configure.ac:7: but the definition used by this AM_INIT_AUTOMAKE
configure.ac:7: comes from Automake 1.15.  You should recreate
configure.ac:7: aclocal.m4 with aclocal and run automake again.
WARNING: 'automake-1.15' is probably too old.
           You should only need it if you modified 'Makefile.am' or
           'configure.ac' or m4 files included by 'configure.ac'.
           The 'automake' program is part of the GNU Automake package:
           <http://www.gnu.org/software/automake>
           It also requires GNU Autoconf, GNU m4 and Perl in order to run:
           <http://www.gnu.org/software/autoconf>
           <http://www.gnu.org/software/m4/>
           <http://www.perl.org/>

When this happens autoreconf (or autogen.sh if available) should be called for that external library. You can manually call it inside the library's source folder under src or choose to set --reconf-LIBRARY option available in top level build scripts which runs autoreconf for you automatically.

All external and supplementary libraries support this option except the libraries listed below.

• Libraries built with CMake don't support reconf option. There are eight libraries built with CMake: chromaprint, cpu-features on Android, libaom, libjpeg-turbo, libvid.stab, snappy, soxr and x265

• Some of the libraries does not come with necessary input files to run autoreconf. For them autoreconf fails with autoreconf: 'configure.ac' or 'configure.in' is required or a similar error message. These libraries are ffmpeg, freetype, libvpx, openh264 and x264