I have been trying to install rgdal from RStudio Version 1.0.44 on ubuntu 16.04 then I was getting the gdal-config not found error. I resolved
I have had some issues trying to install rgdal package but finally I succeeded.
My problem was that gdal > 2.0 is needed, and it does not ship with ubuntu 16.04 by default, so extra packages are needed.
I ended up installing the following packages:
sudo add-apt-repository -y ppa:ubuntugis/ubuntugis-unstable
sudo apt update
sudo apt install gdal-bin python-gdal python3-gdal libgdal1-dev
Additionally, r > 3.3 is needed too, so I ended up updating ubuntu's default r-base installation like this:
sudo add-apt-repository 'deb https://cran.rediris.es/bin/linux/ubuntu xenial/'
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E084DAB9
sudo apt update
Hope it works for you too.