[CMake] [ctest]: Running git clean before building?

[Johan Björk]

Hi everyone,

Unfortunately our buildsystem is not yet entirely clean, and produces
a few files in the source directory. I would like to be able to run
git clean before building, anyone have any ideas how to do this?
(Without losing cdash update history)
To be more precise, the commands I would like to run are the following

git clean -dfx
git submodule foreach clean -dfx

Thanks in advance
/Johan