What Ubuntu package provides a specific file?

There's a tool call apt-file that comes to the rescue. You don't havw to have the package installed, to figure out what package would provide a specific file, like a development header.

It's probably not installed by default, so you'll have to install it.

sudo apt-get install apt-file

Then, make sure the cache is updated.

sudo apt-file update

Now, you can search for the package that has a specific file, like gl.h.

apt-file search "gl.h"