CPostgreSQL
Install PostgreSQL via Homebrew (macOS)
Visit the https://brew.sh to install Homebrew if it isn't already installed.
brew doctor
brew update
brew install postgresql
Install PostgreSQL with Postgres.app (macOS)
Download Postgres.app from http://postgresapp.com
Create a pkgConfig file (/usr/local/lib/pkgconfig/libpq.pc)
with the following content adjusting the path as necessary.
path=/Applications/Postgres.app/Contents/Versions/latest
Cflags: -I${path}/include
Libs: -L${path}/lib -lpq
Install PostgreSQL via apt-get (Linux)
apt-get update
apt-get upgrade
apt-get install postgresql postgresql-contrib