Using QtCreator I have the following in my .gitignore
*build-*
This lets me ignore everything inside the buildfolder, which depending on platform and build tools can have different names starting with build-.
Now I would like to unignore subdirectories inside this folder, such as images and backup and I assummed all I had to do was 
!build-*/**/
But this has no effect, git status doesn't pick up any of the files in the subdirectories of build-*.
What am I missing?