I recently tried to build gazebo-9 from source based on the tutorial here and I noticed that this tutorial and all the tutorials for installing the dependencies from source tell you to download the source code and build it from the
/tmp directory. Later they claim that the uninstall method is to go into the build directory and
sudo make uninstall. However, if you have to reboot at any time in between building and uninstalling, the build directory gets wiped.
I'm not sure what the reason is building in the
/tmp directory, but maybe there is a good reason and explanation could be added to the tutorial.
I'm still having issues with my source install and I documented it here.