This made my IDE unhappy; `ConfigFilePath` is an exported function, so
it makes sense to use the same signature for both Linux and Windows.
This patch also adds error handling (same as on Linux), even though the
current implementation will never return an error (it's good practice
to handle errors, so I assumed this would be the right approach)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>