util_get_directory_variants
Description:
[ Version ( since = "3.40" ) ]
public GenericArray<unowned string> util_get_directory_variants (string main_path, string replace_prefix, bool with_modules_dir)
The main_path is a directory, which will be always used.
 It should have as its prefix the replace_prefix, otherwise the function returns only the main_path in the paths 
      array.
When there's exported an environment variable EDS_EXTRA_PREFIXES, it is used as a list of alternative prefixes where to look for the 
        main_path (rest after the replace_prefix).
When the with_modules_dir is true, there's also added 
      get_user_data_dir + "evolution/modules/", aka 
      ~/.local/share/evolution/modules/, into the resulting array.
Parameters:
| main_path | the main path to work with | 
| replace_prefix | path prefix to replace | 
| with_modules_dir | whether to add also the modules directory | 
Returns:
| a gptrarray  with paths to use, including the  |