Error with APT installation (regex warning, PostGIS fails)

All,

A few errors have popped up today using the APT repo that have otherwise been rock solid for quite a while:

1) PostGIS does not install/load as it used to - no errors beyond what 2) below reports

- Instructions usually used found here: http://trac.osgeo.org/postgis/wiki/UsersWikiPostGIS22UbuntuPGSQL95Apt

2) Strange error coming up that I can only paste and step aside... the error is thrown when using the instructions on the APT repo verbatim, and when using the instructions we've modified above for the PostGIS install...also throws an error when pulling PG v9.6 and v9.5

(...)
Setting up pgdg-keyring (2014.1) ...
Removing apt.postgresql.org key from trusted.gpg: OK
Importing apt.postgresql.org key: OK
Setting up postgresql-client-common (177.pgdg16.04+1) ...
Setting up postgresql-client-9.5 (9.5.5-1.pgdg16.04+1) ...
update-alternatives: using /usr/share/postgresql/9.5/man/man1/psql.1.gz to provide /usr/share/man/man1/psql.1.gz (psql.1.gz) in auto mode
Setting up postgresql-common (177.pgdg16.04+1) ...
Adding user postgres to group ssl-cert

Creating config file /etc/postgresql-common/createcluster.conf with new version

Creating config file /etc/logrotate.d/postgresql-common with new version
Building PostgreSQL dictionaries from installed myspell/hunspell packages...
  en_us
Removing obsolete dictionary files:
Setting up postgresql-9.5 (9.5.5-1.pgdg16.04+1) ...
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at /usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at /usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at /usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at /usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at /usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at /usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at /usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at /usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at /usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at /usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at /usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at /usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at /usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at /usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at /usr/sbin/pam_getenv line 78.
Creating new cluster 9.5/main ...
  config /etc/postgresql/9.5/main
  data   /var/lib/postgresql/9.5/main
  locale en_US.UTF-8
  socket /var/run/postgresql
  port   5432
update-alternatives: using /usr/share/postgresql/9.5/man/man1/postmaster.1.gz to provide /usr/share/man/man1/postmaster.1.gz (postmaster.1.gz) in auto mode
Processing triggers for libc-bin (2.23-0ubuntu4) ...
Processing triggers for systemd (229-4ubuntu12) ...
Processing triggers for ureadahead (0.100.0-19) ...


Many thanks and hope there is a solution...

Matthew Baker
Denver Public Schools
Denver, CO, USA
matthew_baker@dpsk12.org