The paths `C:` (on WIN32) and `/` on other systems was detecting as relative. This meant `BLI_path_abs_from_cwd` would make both paths CWD relative. Also remove duplicate call to BLI_path_is_unc.
The paths `C:` (on WIN32) and `/` on other systems was detecting as relative. This meant `BLI_path_abs_from_cwd` would make both paths CWD relative. Also remove duplicate call to BLI_path_is_unc.