Update: The fake program should check file existence when clean is combined with...

Update: The fake program should check file existence when clean is combined with another command like build or make.

When the make or build command is specified after a clean command, the clean command should do an appropriate file dependency check.
This acts as a safety measure such that if the make or build command could not normally be run due to the missing required files, then the clean operation should not be run.

Rename a related function to a shorter name.