autoconf and libnumbertext dependency

Hi all, 

I think f1579d3d6c5f5f3a6 has a problem.... the new library needs Autoconf version 2.68, but this 
is not what we bundle in LibreOffice. 

I get the following error:

main::scan_file() called too early to check prototype at /opt/lo/bin/aclocal line 617.
configure.ac:6: error: Autoconf version 2.68 or higher is required
configure.ac:6: the top level
autom4te: /usr/bin/m4 failed with exit status: 63
aclocal: /opt/lo/bin/autom4te failed with exit status: 63
autoreconf: aclocal failed with exit status: 63
make[1]: *** [/Users/5K/lo/core/external/libnumbertext/ExternalProject_libnumbertext.mk:30: 
/Users/5K/lo/core/workdir/ExternalProject/libnumbertext/build] Error 1
make[1]: *** Waiting for unfinished jobs….

I’m running on MacOS High Sierra. 

Chris