Reconf Option

When version of Autotools applications installed on 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/>

It does not happen frequently but when it does, autoreconf (or autogen.sh if available) should be called for that external library. You can manually call it in library's source folder under src or set --reconf-LIBRARY option available in top level build scripts which does it for you automatically.

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

• Libraries built with CMake are not affected by this issue. There are seven libraries built with CMake: chromaprint, libaom, libjpeg-turbo (since v2.1), 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 message. They are ffmpeg, freetype, libvpx, openh264 and x264.