Install PosgreSQL 9.4 with PostGIS on OpenShift, configure to use only unix domain socket.

postgis_openshift.sh

# Postgres
cd $OPENSHIFT_DATA_DIR
wget https://ftp.postgresql.org/pub/source/v9.4.7/postgresql-9.4.7.tar.gz
tar xf postgresql-9.4.7.tar.gz
mkdir $OPENSHIFT_DATA_DIR/root
cd postgresql-9.4.7
./configure --prefix=$OPENSHIFT_DATA_DIR/root
make
make install
cd $OPENSHIFT_DATA_DIR
mkdir db
cd $OPENSHIFT_DATA_DIR/root/bin
initdb --locale en_US.UTF-8 -D $OPENSHIFT_DATA_DIR/db/data
cd $OPENSHIFT_DATA_DIR
rm -rf postgresql-9.4.7*

# Geos
wget http://download.osgeo.org/geos/geos-3.5.0.tar.bz2
tar xf geos-3.5.0.tar.bz2 
cd geos-3.5.0
./configure --prefix=$OPENSHIFT_DATA_DIR/root
make
make install
cd $OPENSHIFT_DATA_DIR
rm -rf geos-3.5.0*

# Proj4
wget https://github.com/OSGeo/proj.4/archive/4.9.2.tar.gz
tar xf 4.9.2.tar.gz 
cd proj.4-4.9.2/
./configure --prefix=$OPENSHIFT_DATA_DIR/root
make
make install
cd $OPENSHIFT_DATA_DIR
rm 4.9.2.tar.gz 
rm -rf proj.4-4.9.2

# Postgis
wget http://download.osgeo.org/postgis/source/postgis-2.2.2.tar.gz
tar xf postgis-2.2.2.tar.gz
cd postgis-2.2.2
./configure --with-pgconfig=$OPENSHIFT_DATA_DIR/root/bin/pg_config --with-geosconfig=$OPENSHIFT_DATA_DIR/root/bin/geos-config --with-projdir=$OPENSHIFT_DATA_DIR/root/ --prefix=$OPENSHIFT_DATA_DIR/root
make
make install
cp extensions/postgis/postgis.control ../root/share/postgresql/extension/
cp extensions/postgis/sql_bits/postgis.sql ../root/share/postgresql/extension/postgis--2.2.2.sql
cd $OPENSHIFT_DATA_DIR
rm -rf postgis-2.2.2*

# Configure to use only unix domain socket
echo "listen_addresses = ''" >> $OPENSHIFT_DATA_DIR/db/data/postgresql.conf

# Run
$OPENSHIFT_DATA_DIR/root/bin/postgres -D $OPENSHIFT_DATA_DIR/db/data

Don't forget to:

$OPENSHIFT_DATA_DIR/root/bin/psql -d <your-database> -c "CREATE EXTENSION postgis;"