al_insert_path_component
void al_insert_path_component(ALLEGRO_PATH *path, int i, const char *s)
Insert a directory component at index i. If the index is negative then count from the right, i.e. -1 refers to the last path component.
It is an error to pass an index i which is not within these bounds: 0 <= i <= al_get_path_num_components(path).
See also: al_append_path_component, al_replace_path_component, al_remove_path_component
Examples: ex_path_test