The problem was introduced in 636f3697ee
MacOS has a different way of handling the title.
In this OS the directory is searched and taken from the title string
which is then formatted.
This limits the title format and makes it prone to errors.
This commit makes the code more generic by splitting each component of
the title beforehand and allowing the associated directory to be informed
with `GHOST_SetTitle`.
Pull Request: https://projects.blender.org/blender/blender/pulls/113227
bd6b7088bf