Segmentation fault (core dumped) during Nominatim 3.1.0 installation Create DB

Hello,

I am attempting to install Nominatim on Ubuntu 14.04 with php5. During the attempt to run setup.php it fails on this line: https://github.com/openstreetmap/Nominatim/blob/master/utils/setup.php#L88

With output:

2018-07-04 06:31:38 == Create DB
Segmentation fault (core dumped)

My version of PEAR::DB is 1.9.2.

If I deliberately break the connection string, it will return a 'DB not available' error without throwing a segfault. The command I ran was:

./utils/setup.php --osm-file /srv/nominatim/australia-latest.osm.pbf --all 2>&1

I get the same results if I run with root (I know that the setup instructions warn against installing as root).