It looks like in Ubuntu that header is part of the libpq-dev package (at least in the following Ubuntu versions:
11.04 (Natty Narwhal), 10.04 (Lucid Lynx), 11.10 (Oneiric Ocelot), 12.04 (Precise Pangolin), 14.04 (Trusty Tahr) and 18.04 (Bionic Beaver)):
...
/usr/include/postgresql/libpq-fe.h
...
So try installing libpq-dev or its equivalent for your OS:
- For Ubuntu/Debian systems:
sudo apt-get install libpq-dev - On Red Hat Linux (RHEL) systems:
yum install postgresql-devel - For Mac Homebrew:
brew install postgresql - For Mac MacPorts PostgreSQL:
gem install pg -- --with-pg-config=/opt/local/lib/postgresql[version number]/bin/pg_config - For OpenSuse:
zypper in postgresql-devel - For ArchLinux:
pacman -S postgresql-libs