Remove uses of get_current_dir_name

[kojix2]

This pull request removes get_current_dir_name to make seqwish easier to compile on macOS.

• https://github.com/ekg/seqwish/issues/117

Created based on the following pull request

• https://github.com/pangenome/odgi/pull/494/commits/ef57bea30162e7213b57c5eaec8c74c50fa3f0a1