[horde] Could not instantiate PDO...

[Michael C. Robinson]

PDOException: could not find driver in
/opt/lib/php/Horde/Db/Adapter/Pdo/Base.php on line 48

webmail-install bombs out with this.

I'm running CentOS-7 in Virtualbox and I am trying to connect to a real
hardware postgresql production server that is working.  This is a
research setup to figure out how to migrate my CentOS 6.x servers to
CentOS 7.x.

I entered the username and password as well as the database name
correctly.

>From what I have seen on google, pecl install pdo is deprecated.  What
confuses me is that the test script says I have postgresql and mysql
support which I compiled in after I configured php-5.6.16.

Configured php with:

./configure --prefix=/opt \
            --sysconfdir=/opt/conf \
            --enable-fpm \
            --with-fpm-user=apache \
            --with-fpm-group=apache \
            --with-config-file-path=/opt/conf \
            --with-zlib \
            --enable-bcmath \
            --with-bz2 \
            --enable-calendar \
            --enable-dba=shared \
            --with-gdbm \
            --with-gd \
            --enable-intl \
            --with-gmp \
            --enable-ftp \
            --with-gettext \
            --enable-mbstring \
            --with-pgsql \
            --with-mysql \
            --with-openssl \
            --with-tidy \
            --with-readline

So I am wondering, if PDO is a deprecated extension why is horde-5.2.8
trying to use it?  I thought horde is up to 5.2.11, how do I upgrade?