Do all functions of taxonomy_context need PHP 5.2?

Hi,
I have a provider which doesn't have PHP 5.2 yet, and may be not until late in 2010.
I am porting a module to drupal 6. Openresort. And in this module some taxonomy_context functions are used:
- taxonomy_context_get_context();
- taxonomy_context_get_breadcrumb($context);

Can I temporarely extract those and relations out of taxonomy_context, or can I remove the dependency if only these functions are touched?

Thanks a lot in advance for your reply!
Greetings, Martijn